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Farleigh K, Ascanio A, Farleigh ME, Schield DR, Card DC, Leal M, Castoe TA, Jezkova T, Rodríguez-Robles JA. Signals of differential introgression in the genome of natural hybrids of Caribbean anoles. Mol Ecol 2023; 32:6000-6017. [PMID: 37861454 DOI: 10.1111/mec.17170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 08/30/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023]
Abstract
Hybridization facilitates recombination between divergent genetic lineages and can be shaped by both neutral and selective processes. Upon hybridization, loci with no net fitness effects introgress randomly from parental species into the genomes of hybrid individuals. Conversely, alleles from one parental species at some loci may provide a selective advantage to hybrids, resulting in patterns of introgression that do not conform to random expectations. We investigated genomic patterns of differential introgression in natural hybrids of two species of Caribbean anoles, Anolis pulchellus and A. krugi in Puerto Rico. Hybrids exhibit A. pulchellus phenotypes but possess A. krugi mitochondrial DNA, originated from multiple, independent hybridization events, and appear to have replaced pure A. pulchellus across a large area in western Puerto Rico. Combining genome-wide SNP datasets with bioinformatic methods to identify signals of differential introgression in hybrids, we demonstrate that the genomes of hybrids are dominated by pulchellus-derived alleles and show only 10%-20% A. krugi ancestry. The majority of A. krugi loci in hybrids exhibit a signal of non-random differential introgression and include loci linked to genes involved in development and immune function. Three of these genes (delta like canonical notch ligand 1, jagged1 and notch receptor 1) affect cell differentiation and growth and interact with mitochondrial function. Our results suggest that differential non-random introgression for a subset of loci may be driven by selection favouring the inheritance of compatible mitochondrial and nuclear-encoded genes in hybrids.
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Affiliation(s)
- Keaka Farleigh
- Department of Biology, Miami University, Oxford, Ohio, USA
| | | | | | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Daren C Card
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Manuel Leal
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Todd A Castoe
- Department of Biology, University of Texas, Arlington, Arlington, Texas, USA
| | - Tereza Jezkova
- Department of Biology, Miami University, Oxford, Ohio, USA
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2
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Smith CF, Nikolakis ZL, Perry BW, Schield DR, Meik JM, Saviola AJ, Castoe TA, Parker J, Mackessy SP. The best of both worlds? Rattlesnake hybrid zones generate complex combinations of divergent venom phenotypes that retain high toxicity. Biochimie 2023; 213:176-189. [PMID: 37451532 DOI: 10.1016/j.biochi.2023.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/27/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Studying the consequences of hybridization between closely related species with divergent traits can reveal patterns of evolution that shape and maintain extreme trophic adaptations. Snake venoms are an excellent model system for examining the evolutionary and ecological patterns that underlie highly selected polymorphic traits. Here we investigate hybrid venom phenotypes that result from natural introgression between two rattlesnake species that express highly divergent venom phenotypes: Crotalus o. concolor and C. v. viridis. Though not yet documented, interbreeding between these species may lead to novel venom phenotypes with unique activities that break the typical trends of venom composition in rattlesnakes. The characteristics of these unusual phenotypes could unveil the roles of introgression in maintaining patterns of venom composition and variation, including the near ubiquitous dichotomy between neurotoxic or degradative venoms observed across rattlesnakes. We use RADseq data to infer patterns of gene flow and hybrid ancestry between these diverged lineages and link these genetic data with analyses of venom composition, biological activity, and whole animal model toxicity tests to understand the impacts of introgression on venom composition. We find that introgressed populations express admixed venom phenotypes that do not sacrifice biological activity (lethal toxicity) or overall abundance of dominant toxins compared to parental venoms. These hybridized venoms therefore do not represent a trade-off in functionality between the typical phenotypic extremes but instead represent a unique combination of characters whose expression appears limited to the hybrid zone.
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Affiliation(s)
- Cara F Smith
- School of Biological Sciences, 501 20th Street, University of Northern Colorado, Greeley, CO, 80639, USA
| | - Zachary L Nikolakis
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, 1333 W. Washington Street, Stephenville, TX, 76402, USA
| | - Anthony J Saviola
- Department of Biochemistry and Molecular Genetics, 12801 East 17th Avenue, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Todd A Castoe
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Joshua Parker
- Fresno City College, 1101 E. University Avenue, Fresno, CA, 93741, USA
| | - Stephen P Mackessy
- School of Biological Sciences, 501 20th Street, University of Northern Colorado, Greeley, CO, 80639, USA.
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3
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Smith CF, Nikolakis ZL, Ivey K, Perry BW, Schield DR, Balchan NR, Parker J, Hansen KC, Saviola AJ, Castoe TA, Mackessy SP. Snakes on a plain: biotic and abiotic factors determine venom compositional variation in a wide-ranging generalist rattlesnake. BMC Biol 2023; 21:136. [PMID: 37280596 DOI: 10.1186/s12915-023-01626-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 05/12/2023] [Indexed: 06/08/2023] Open
Abstract
BACKGROUND Snake venoms are trophic adaptations that represent an ideal model to examine the evolutionary factors that shape polymorphic traits under strong natural selection. Venom compositional variation is substantial within and among venomous snake species. However, the forces shaping this phenotypic complexity, as well as the potential integrated roles of biotic and abiotic factors, have received little attention. Here, we investigate geographic variation in venom composition in a wide-ranging rattlesnake (Crotalus viridis viridis) and contextualize this variation by investigating dietary, phylogenetic, and environmental variables that covary with venom. RESULTS Using shotgun proteomics, venom biochemical profiling, and lethality assays, we identify 2 distinct divergent phenotypes that characterize major axes of venom variation in this species: a myotoxin-rich phenotype and a snake venom metalloprotease (SVMP)-rich phenotype. We find that dietary availability and temperature-related abiotic factors are correlated with geographic trends in venom composition. CONCLUSIONS Our findings highlight the potential for snake venoms to vary extensively within species, for this variation to be driven by biotic and abiotic factors, and for the importance of integrating biotic and abiotic variation for understanding complex trait evolution. Links between venom variation and variation in biotic and abiotic factors indicate that venom variation likely results from substantial geographic variation in selection regimes that determine the efficacy of venom phenotypes across populations and snake species. Our results highlight the cascading influence of abiotic factors on biotic factors that ultimately shape venom phenotype, providing evidence for a central role of local selection as a key driver of venom variation.
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Affiliation(s)
- Cara F Smith
- Department of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, 12801 East 17th Avenue, Aurora, CO, 80045, USA
| | - Zachary L Nikolakis
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Kathleen Ivey
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76019, USA
- Current address: Department of Ecology & Evolutionary Biology, University of Colorado, 1900 Pleasant Street, Boulder, CO, 80309, USA
| | - Neil R Balchan
- Department of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA
| | - Joshua Parker
- Fresno City College, 1101 E. University Avenue, Fresno, CA, 93741, USA
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, 12801 East 17th Avenue, Aurora, CO, 80045, USA
| | - Anthony J Saviola
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, 12801 East 17th Avenue, Aurora, CO, 80045, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Stephen P Mackessy
- Department of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA.
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4
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Carter JK, Kimball RT, Funk ER, Kane NC, Schield DR, Spellman GM, Safran RJ. Estimating phylogenies from genomes: A beginners review of commonly used genomic data in vertebrate phylogenomics. J Hered 2023; 114:1-13. [PMID: 36808491 DOI: 10.1093/jhered/esac061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/26/2022] [Indexed: 02/20/2023] Open
Abstract
Despite the increasing feasibility of sequencing whole genomes from diverse taxa, a persistent problem in phylogenomics is the selection of appropriate genetic markers or loci for a given taxonomic group or research question. In this review, we aim to streamline the decision-making process when selecting specific markers to use in phylogenomic studies by introducing commonly used types of genomic markers, their evolutionary characteristics, and their associated uses in phylogenomics. Specifically, we review the utilities of ultraconserved elements (including flanking regions), anchored hybrid enrichment loci, conserved nonexonic elements, untranslated regions, introns, exons, mitochondrial DNA, single nucleotide polymorphisms, and anonymous regions (nonspecific regions that are evenly or randomly distributed across the genome). These various genomic elements and regions differ in their substitution rates, likelihood of neutrality or of being strongly linked to loci under selection, and mode of inheritance, each of which are important considerations in phylogenomic reconstruction. These features may give each type of marker important advantages and disadvantages depending on the biological question, number of taxa sampled, evolutionary timescale, cost effectiveness, and analytical methods used. We provide a concise outline as a resource to efficiently consider key aspects of each type of genetic marker. There are many factors to consider when designing phylogenomic studies, and this review may serve as a primer when weighing options between multiple potential phylogenomic markers.
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Affiliation(s)
- Javan K Carter
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States
- Genomics, Bioinformatics, and Translational Research Center, Research Triangle Institute International, RTP, NC, United States
| | - Rebecca T Kimball
- Department of Biology, University of Florida, Gainesville, FL, United States
| | - Erik R Funk
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States
- Department of Conservation Genetics, San Diego Zoo Wildlife Alliance, Escondido, CA, United States
| | - Nolan C Kane
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States
| | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature and Science, Denver, CO, United States
| | - Rebecca J Safran
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, United States
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5
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Nikolakis ZL, Schield DR, Westfall AK, Perry BW, Ivey KN, Orton RW, Hales NR, Adams RH, Meik JM, Parker JM, Smith CF, Gompert Z, Mackessy SP, Castoe TA. Evidence that genomic incompatibilities and other multilocus processes impact hybrid fitness in a rattlesnake hybrid zone. Evolution 2022; 76:2513-2530. [PMID: 36111705 DOI: 10.1111/evo.14612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 06/24/2022] [Accepted: 08/15/2022] [Indexed: 01/22/2023]
Abstract
Hybrid zones provide valuable opportunities to understand the genomic mechanisms that promote speciation by providing insight into factors involved in intermediate stages of speciation. Here, we investigate introgression in a hybrid zone between two rattlesnake species (Crotalus viridis and Crotalus oreganus concolor) that have undergone historical allopatric divergence and recent range expansion and secondary contact. We use Bayesian genomic cline models to characterize genomic patterns of introgression between these lineages and identify loci potentially subject to selection in hybrids. We find evidence for a large number of genomic regions with biased ancestry that deviate from the genomic background in hybrids (i.e., excess ancestry loci), which tend to be associated with genomic regions with higher recombination rates. We also identify suites of excess ancestry loci that show highly correlated allele frequencies (including conspecific and heterospecific combinations) across physically unlinked genomic regions in hybrids. Our findings provide evidence for multiple multilocus evolutionary processes impacting hybrid fitness in this system.
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Affiliation(s)
- Zachary L Nikolakis
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Kathleen N Ivey
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard W Orton
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
| | - Richard H Adams
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, Georgia, 31061
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas, 76402
| | - Joshua M Parker
- Department of Life Sciences, Fresno City College, Fresno, California, 93741
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado, 80639
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, 76019
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6
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Schield DR, Perry BW, Adams RH, Holding ML, Nikolakis ZL, Gopalan SS, Smith CF, Parker JM, Meik JM, DeGiorgio M, Mackessy SP, Castoe TA. The roles of balancing selection and recombination in the evolution of rattlesnake venom. Nat Ecol Evol 2022; 6:1367-1380. [PMID: 35851850 PMCID: PMC9888523 DOI: 10.1038/s41559-022-01829-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 06/15/2022] [Indexed: 02/02/2023]
Abstract
The origin of snake venom involved duplication and recruitment of non-venom genes into venom systems. Several studies have predicted that directional positive selection has governed this process. Venom composition varies substantially across snake species and venom phenotypes are locally adapted to prey, leading to coevolutionary interactions between predator and prey. Venom origins and contemporary snake venom evolution may therefore be driven by fundamentally different selection regimes, yet investigations of population-level patterns of selection have been limited. Here, we use whole-genome data from 68 rattlesnakes to test hypotheses about the factors that drive genomic diversity and differentiation in major venom gene regions. We show that selection has resulted in long-term maintenance of genetic diversity within and between species in multiple venom gene families. Our findings are inconsistent with a dominant role of directional positive selection and instead support a role of long-term balancing selection in shaping venom evolution. We also detect rapid decay of linkage disequilibrium due to high recombination rates in venom regions, suggesting that venom genes have reduced selective interference with nearby loci, including other venom paralogues. Our results provide an example of long-term balancing selection that drives trans-species polymorphism and help to explain how snake venom keeps pace with prey resistance.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Richard H Adams
- Department of Biological and Environmental Sciences, Georgia College and State University, Milledgeville, GA, USA
| | | | | | | | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Joshua M Parker
- Life Science Department, Fresno City College, Fresno, CA, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, TX, USA
| | - Michael DeGiorgio
- Department of Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
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7
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Schield DR, Perry BW, Card DC, Pasquesi GIM, Westfall AK, Mackessy SP, Castoe TA. The rattlesnake W chromosome: A GC-rich retroelement refugium with retained gene function across ancient evolutionary strata. Genome Biol Evol 2022; 14:6648526. [PMID: 35867356 PMCID: PMC9447483 DOI: 10.1093/gbe/evac116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2022] [Indexed: 11/18/2022] Open
Abstract
Sex chromosomes diverge after the establishment of recombination suppression, resulting in differential sex-linkage of genes involved in genetic sex determination and dimorphic traits. This process produces systems of male or female heterogamety wherein the Y and W chromosomes are only present in one sex and are often highly degenerated. Sex-limited Y and W chromosomes contain valuable information about the evolutionary transition from autosomes to sex chromosomes, yet detailed characterizations of the structure, composition, and gene content of sex-limited chromosomes are lacking for many species. In this study, we characterize the female-specific W chromosome of the prairie rattlesnake (Crotalus viridis) and evaluate how recombination suppression and other processes have shaped sex chromosome evolution in ZW snakes. Our analyses indicate that the rattlesnake W chromosome is over 80% repetitive and that an abundance of GC-rich mdg4 elements has driven an overall high degree of GC-richness despite a lack of recombination. The W chromosome is also highly enriched for repeat sequences derived from endogenous retroviruses and likely acts as a “refugium” for these and other retroelements. We annotated 219 putatively functional W-linked genes across at least two evolutionary strata identified based on estimates of sequence divergence between Z and W gametologs. The youngest of these strata is relatively gene-rich, however gene expression across strata suggests retained gene function amidst a greater degree of degeneration following ancient recombination suppression. Functional annotation of W-linked genes indicates a specialization of the W chromosome for reproductive and developmental function since recombination suppression from the Z chromosome.
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Affiliation(s)
- Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.,School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Daren C Card
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.,Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Giulia I M Pasquesi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
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8
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Gopalan SS, Perry BW, Schield DR, Smith CF, Mackessy SP, Castoe TA. Origins, genomic structure and copy number variation of snake venom myotoxins. Toxicon 2022; 216:92-106. [PMID: 35820472 DOI: 10.1016/j.toxicon.2022.06.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/21/2022] [Accepted: 06/27/2022] [Indexed: 10/17/2022]
Abstract
Crotamine, myotoxin a and homologs are short peptides that often comprise major fractions of rattlesnake venoms and have been extensively studied for their bioactive properties. These toxins are thought to be important for rapidly immobilizing mammalian prey and are implicated in serious, and sometimes fatal, responses to envenomation in humans. While high quality reference genomes for multiple venomous snakes are available, the loci that encode myotoxins have not been successfully assembled in any existing genome assembly. Here, we integrate new and existing genomic and transcriptomic data from the Prairie Rattlesnake (Crotalus viridis viridis) to reconstruct, characterize, and infer the chromosomal locations of myotoxin-encoding loci. We integrate long-read transcriptomics (Pacific Bioscience's Iso-Seq) and short-read RNA-seq to infer gene sequence diversity and characterize patterns of myotoxin and paralogous β-defensin expression across multiple tissues. We also identify two long non-coding RNA sequences which both encode functional myotoxins, demonstrating a newly discovered source of venom coding sequence diversity. We also integrate long-range mate-pair chromatin contact data and linked-read sequencing to infer the structure and chromosomal locations of the three myotoxin-like loci. Further, we conclude that the venom-associated myotoxin is located on chromosome 1 and is adjacent to non-venom paralogs. Consistent with this locus contributing to venom composition, we find evidence that the promoter of this gene is selectively open in venom gland tissue and contains transcription factor binding sites implicated in broad trans-regulatory pathways that regulate snake venoms. This study provides the best genomic reconstruction of myotoxin loci to date and raises questions about the physiological roles and interplay between myotoxin and related genes, as well as the genomic origins of snake venom variation.
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Affiliation(s)
- Siddharth S Gopalan
- Department of Biology, 501 S. Nedderman Dr., The University of Texas Arlington, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, 501 S. Nedderman Dr., The University of Texas Arlington, Arlington, TX, 76019, USA; School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Cara F Smith
- School of Biological Sciences, 501 20th Street, University of Northern Colorado, Greeley, CO, 80639, USA; Department of Biochemistry and Molecular Biology, 12801 East 17th Avenue, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Stephen P Mackessy
- School of Biological Sciences, 501 20th Street, University of Northern Colorado, Greeley, CO, 80639, USA
| | - Todd A Castoe
- Department of Biology, 501 S. Nedderman Dr., The University of Texas Arlington, Arlington, TX, 76019, USA.
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9
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Perry BW, Gopalan SS, Pasquesi GIM, Schield DR, Westfall AK, Smith CF, Koludarov I, Chippindale PT, Pellegrino MW, Chuong EB, Mackessy SP, Castoe TA. Snake venom gene expression is coordinated by novel regulatory architecture and the integration of multiple co-opted vertebrate pathways. Genome Res 2022; 32:1058-1073. [PMID: 35649579 PMCID: PMC9248877 DOI: 10.1101/gr.276251.121] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/11/2022] [Indexed: 11/25/2022]
Abstract
Understanding how regulatory mechanisms evolve is critical for understanding the processes that give rise to novel phenotypes. Snake venom systems represent a valuable and tractable model for testing hypotheses related to the evolution of novel regulatory networks, yet the regulatory mechanisms underlying venom production remain poorly understood. Here, we use functional genomics approaches to investigate venom regulatory architecture in the prairie rattlesnake and identify cis-regulatory sequences (enhancers and promoters), trans-regulatory transcription factors, and integrated signaling cascades involved in the regulation of snake venom genes. We find evidence that two conserved vertebrate pathways, the extracellular signal-regulated kinase and unfolded protein response pathways, were co-opted to regulate snake venom. In one large venom gene family (snake venom serine proteases), this co-option was likely facilitated by the activity of transposable elements. Patterns of snake venom gene enhancer conservation, in some cases spanning 50 million yr of lineage divergence, highlight early origins and subsequent lineage-specific adaptations that have accompanied the evolution of venom regulatory architecture. We also identify features of chromatin structure involved in venom regulation, including topologically associated domains and CTCF loops that underscore the potential importance of novel chromatin structure to coevolve when duplicated genes evolve new regulatory control. Our findings provide a model for understanding how novel regulatory systems may evolve through a combination of genomic processes, including tandem duplication of genes and regulatory sequences, cis-regulatory sequence seeding by transposable elements, and diverse transcriptional regulatory proteins controlled by a co-opted regulatory cascade.
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Affiliation(s)
- Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA.,School of Biological Sciences, Washington State University, Pullman, Washington 99164, USA
| | - Siddharth S Gopalan
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Giulia I M Pasquesi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Ivan Koludarov
- Animal Venomics Group, Justus Liebig University, Giessen, 35390, Germany
| | - Paul T Chippindale
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Mark W Pellegrino
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA
| | - Edward B Chuong
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76019, USA
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10
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Turbek SP, Schield DR, Scordato ESC, Contina A, Da XW, Liu Y, Liu Y, Pagani-Núñez E, Ren QM, Smith CCR, Stricker CA, Wunder M, Zonana DM, Safran RJ. A migratory divide spanning two continents is associated with genomic and ecological divergence. Evolution 2022; 76:722-736. [PMID: 35166383 DOI: 10.1111/evo.14448] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 12/21/2021] [Accepted: 12/29/2021] [Indexed: 01/22/2023]
Abstract
Migratory divides are contact zones between breeding populations with divergent migratory strategies during the nonbreeding season. These locations provide an opportunity to evaluate the role of seasonal migration in the maintenance of reproductive isolation, particularly the relationship between population structure and features associated with distinct migratory strategies. We combine light-level geolocators, genomic sequencing, and stable isotopes to investigate the timing of migration and migratory routes of individuals breeding on either side of a migratory divide coinciding with genomic differentiation across a hybrid zone between barn swallow (Hirundo rustica) subspecies in China. Individuals west of the hybrid zone, with H. r. rustica ancestry, had comparatively enriched stable-carbon and hydrogen isotope values and overwintered in eastern Africa, whereas birds east of the hybrid zone, with H. r. gutturalis ancestry, had depleted isotope values and migrated to southern India. The two subspecies took divergent migratory routes around the high-altitude Karakoram Range and arrived on the breeding grounds over 3 weeks apart. These results indicate that assortative mating by timing of arrival and/or selection against hybrids with intermediate migratory traits may maintain reproductive isolation between the subspecies, and that inhospitable geographic features may have contributed to the diversification of Asian avifauna by influencing migratory patterns.
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Affiliation(s)
- Sheela P Turbek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Elizabeth S C Scordato
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309.,Department of Biological Sciences, Cal Poly Pomona, Pomona, California, 91768
| | - Andrea Contina
- Department of Integrative Biology, University of Colorado, Denver, Colorado, 80217
| | - Xin-Wei Da
- College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Yang Liu
- School of Ecology, Sun Yat-sen University, Guangzhou, 510275, China
| | - Yu Liu
- Key Laboratory for Biodiversity Sciences and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing, 100875, China
| | - Emilio Pagani-Núñez
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, China
| | - Qing-Miao Ren
- School of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Chris C R Smith
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
| | - Craig A Stricker
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, 80526
| | - Michael Wunder
- Department of Integrative Biology, University of Colorado, Denver, Colorado, 80217
| | - David M Zonana
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309.,Department of Biological Sciences, University of Denver, Denver, Colorado, 80210
| | - Rebecca J Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309
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11
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Koochekian N, Ascanio A, Farleigh K, Card DC, Schield DR, Castoe TA, Jezkova T. A chromosome-level genome assembly and annotation of the desert horned lizard, Phrynosoma platyrhinos, provides insight into chromosomal rearrangements among reptiles. Gigascience 2022; 11:6521878. [PMID: 35134927 PMCID: PMC8848323 DOI: 10.1093/gigascience/giab098] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 09/27/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The increasing number of chromosome-level genome assemblies has advanced our knowledge and understanding of macroevolutionary processes. Here, we introduce the genome of the desert horned lizard, Phrynosoma platyrhinos, an iguanid lizard occupying extreme desert conditions of the American southwest. We conduct analysis of the chromosomal structure and composition of this species and compare these features across genomes of 12 other reptiles (5 species of lizards, 3 snakes, 3 turtles, and 1 bird). FINDINGS The desert horned lizard genome was sequenced using Illumina paired-end reads and assembled and scaffolded using Dovetail Genomics Hi-C and Chicago long-range contact data. The resulting genome assembly has a total length of 1,901.85 Mb, scaffold N50 length of 273.213 Mb, and includes 5,294 scaffolds. The chromosome-level assembly is composed of 6 macrochromosomes and 11 microchromosomes. A total of 20,764 genes were annotated in the assembly. GC content and gene density are higher for microchromosomes than macrochromosomes, while repeat element distributions show the opposite trend. Pathway analyses provide preliminary evidence that microchromosome and macrochromosome gene content are functionally distinct. Synteny analysis indicates that large microchromosome blocks are conserved among closely related species, whereas macrochromosomes show evidence of frequent fusion and fission events among reptiles, even between closely related species. CONCLUSIONS Our results demonstrate dynamic karyotypic evolution across Reptilia, with frequent inferred splits, fusions, and rearrangements that have resulted in shuffling of chromosomal blocks between macrochromosomes and microchromosomes. Our analyses also provide new evidence for distinct gene content and chromosomal structure between microchromosomes and macrochromosomes within reptiles.
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Affiliation(s)
| | - Alfredo Ascanio
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Keaka Farleigh
- Department of Biology, Miami University, Oxford, OH 45056, USA
| | - Daren C Card
- Department of Organismic & Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.,Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | - Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Tereza Jezkova
- Department of Biology, Miami University, Oxford, OH 45056, USA
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12
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Westfall AK, Perry BW, Kamal AHM, Hales NR, Kay JC, Sapkota M, Schield DR, Pellegrino MW, Secor SM, Chowdhury SM, Castoe TA. Identification of an integrated stress and growth response signaling switch that directs vertebrate intestinal regeneration. BMC Genomics 2022; 23:6. [PMID: 34983392 PMCID: PMC8725436 DOI: 10.1186/s12864-021-08226-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 12/01/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Snakes exhibit extreme intestinal regeneration following months-long fasts that involves unparalleled increases in metabolism, function, and tissue growth, but the specific molecular control of this process is unknown. Understanding the mechanisms that coordinate these regenerative phenotypes provides valuable opportunities to understand critical pathways that may control vertebrate regeneration and novel perspectives on vertebrate regenerative capacities. RESULTS Here, we integrate a comprehensive set of phenotypic, transcriptomic, proteomic, and phosphoproteomic data from boa constrictors to identify the mechanisms that orchestrate shifts in metabolism, nutrient uptake, and cellular stress to direct phases of the regenerative response. We identify specific temporal patterns of metabolic, stress response, and growth pathway activation that direct regeneration and provide evidence for multiple key central regulatory molecules kinases that integrate these signals, including major conserved pathways like mTOR signaling and the unfolded protein response. CONCLUSION Collectively, our results identify a novel switch-like role of stress responses in intestinal regeneration that forms a primary regulatory hub facilitating organ regeneration and could point to potential pathways to understand regenerative capacity in vertebrates.
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Affiliation(s)
- Aundrea K Westfall
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Abu H M Kamal
- Advanced Technology Cores, Baylor College of Medicine, Houston, TX, USA.,Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.,Department of Research Development and Commercialization, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Jarren C Kay
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Madhab Sapkota
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Mark W Pellegrino
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Saiful M Chowdhury
- Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
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13
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Pasquesi GIM, Perry BW, Vandewege MW, Ruggiero RP, Schield DR, Castoe TA. Vertebrate Lineages Exhibit Diverse Patterns of Transposable Element Regulation and Expression across Tissues. Genome Biol Evol 2021; 12:506-521. [PMID: 32271917 PMCID: PMC7211425 DOI: 10.1093/gbe/evaa068] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2020] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) comprise a major fraction of vertebrate genomes, yet little is known about their expression and regulation across tissues, and how this varies across major vertebrate lineages. We present the first comparative analysis integrating TE expression and TE regulatory pathway activity in somatic and gametic tissues for a diverse set of 12 vertebrates. We conduct simultaneous gene and TE expression analyses to characterize patterns of TE expression and TE regulation across vertebrates and examine relationships between these features. We find remarkable variation in the expression of genes involved in TE negative regulation across tissues and species, yet consistently high expression in germline tissues, particularly in testes. Most vertebrates show comparably high levels of TE regulatory pathway activity across gonadal tissues except for mammals, where reduced activity of TE regulatory pathways in ovarian tissues may be the result of lower relative germ cell densities. We also find that all vertebrate lineages examined exhibit remarkably high levels of TE-derived transcripts in somatic and gametic tissues, with recently active TE families showing higher expression in gametic tissues. Although most TE-derived transcripts originate from inactive ancient TE families (and are likely incapable of transposition), such high levels of TE-derived RNA in the cytoplasm may have secondary, unappreciated biological relevance.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington.,Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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14
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Farleigh K, Vladimirova SA, Blair C, Bracken JT, Koochekian N, Schield DR, Card DC, Finger N, Henault J, Leaché AD, Castoe TA, Jezkova T. The effects of climate and demographic history in shaping genomic variation across populations of the Desert Horned Lizard (Phrynosoma platyrhinos). Mol Ecol 2021; 30:4481-4496. [PMID: 34245067 DOI: 10.1111/mec.16070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/30/2022]
Abstract
Species often experience spatial environmental heterogeneity across their range, and populations may exhibit signatures of adaptation to local environmental characteristics. Other population genetic processes, such as migration and genetic drift, can impede the effects of local adaptation. Genetic drift in particular can have a pronounced effect on population genetic structure during large-scale geographic expansions, where a series of founder effects leads to decreases in genetic variation in the direction of the expansion. Here, we explore the genetic diversity of a desert lizard that occupies a wide range of environmental conditions and that has experienced post-glacial expansion northwards along two colonization routes. Based on our analyses of a large SNP data set, we find evidence that both climate and demographic history have shaped the genetic structure of populations. Pronounced genetic differentiation was evident between populations occupying cold versus hot deserts, and we detected numerous loci with significant associations with climate. The genetic signal of founder effects, however, is still present in the genomes of the recently expanded populations, which comprise subsets of genetic variation found in the southern populations.
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Affiliation(s)
- Keaka Farleigh
- Department of Biology, Miami University, Oxford, Ohio, USA
| | | | - Christopher Blair
- Department of Biological Sciences, New York City College of Technology, The City University of New York, Brooklyn, New York, USA.,Biology PhD Program, CUNY Graduate Center, New York, New York, USA
| | | | | | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.,Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, USA
| | - Nicholas Finger
- Department of Biological Sciences, New York City College of Technology, The City University of New York, Brooklyn, New York, USA
| | | | - Adam D Leaché
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, Washington, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, USA
| | - Tereza Jezkova
- Department of Biology, Miami University, Oxford, Ohio, USA
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15
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Perry BW, Schield DR, Adams RH, Castoe TA. Microchromosomes Exhibit Distinct Features of Vertebrate Chromosome Structure and Function with Underappreciated Ramifications for Genome Evolution. Mol Biol Evol 2021; 38:904-910. [PMID: 32986808 PMCID: PMC7947875 DOI: 10.1093/molbev/msaa253] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Microchromosomes are common yet poorly understood components of many vertebrate genomes. Recent studies have revealed that microchromosomes contain a high density of genes and possess other distinct characteristics compared with macrochromosomes. Whether distinctive characteristics of microchromosomes extend to features of genome structure and organization, however, remains an open question. Here, we analyze Hi-C sequencing data from multiple vertebrate lineages and show that microchromosomes exhibit consistently high degrees of interchromosomal interaction (particularly with other microchromosomes), appear to be colocalized to a common central nuclear territory, and are comprised of a higher proportion of open chromatin than macrochromosomes. These findings highlight an unappreciated level of diversity in vertebrate genome structure and function, and raise important questions regarding the evolutionary origins and ramifications of microchromosomes and the genes that they house.
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Affiliation(s)
- Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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16
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Schield DR, Perry BW, Nikolakis ZL, Mackessy SP, Castoe TA. Population Genomic Analyses Confirm Male-Biased Mutation Rates in Snakes. J Hered 2021; 112:221-227. [PMID: 33502475 DOI: 10.1093/jhered/esab005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
Male-biased mutation rates occur in a diverse array of organisms. The ratio of male-to-female mutation rate may have major ramifications for evolution across the genome, and for sex-linked genes in particular. In ZW species, the Z chromosome is carried by males two-thirds of the time, leading to the prediction that male-biased mutation rates will have a disproportionate effect on the evolution of Z-linked genes relative to autosomes and the W chromosome. Colubroid snakes (including colubrids, elapids, and viperids) have ZW sex determination, yet male-biased mutation rates have not been well studied in this group. Here we analyze a population genomic dataset from rattlesnakes to quantify genetic variation within and genetic divergence between species. We use a new method for unbiased estimation of population genetic summary statistics to compare variation between the Z chromosome and autosomes and to calculate net nucleotide differentiation between species. We find evidence for a 2.03-fold greater mutation rate in male rattlesnakes relative to females, corresponding to an average μZ/μA ratio of 1.1. Our results from snakes are quantitatively similar to birds, suggesting that male-biased mutation rates may be a common feature across vertebrate lineages with ZW sex determination.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX.,Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | | | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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17
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Schield DR, Scordato ESC, Smith CCR, Carter JK, Cherkaoui SI, Gombobaatar S, Hajib S, Hanane S, Hund AK, Koyama K, Liang W, Liu Y, Magri N, Rubtsov A, Sheta B, Turbek SP, Wilkins MR, Yu L, Safran RJ. Sex-linked genetic diversity and differentiation in a globally distributed avian species complex. Mol Ecol 2021; 30:2313-2332. [PMID: 33720472 DOI: 10.1111/mec.15885] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/19/2021] [Accepted: 03/10/2021] [Indexed: 12/15/2022]
Abstract
Sex chromosomes often bear distinct patterns of genetic variation due to unique patterns of inheritance and demography. The processes of mutation, recombination, genetic drift and selection also influence rates of evolution on sex chromosomes differently than autosomes. Measuring such differences provides information about how these processes shape genomic variation and their roles in the origin of species. To test hypotheses and predictions about patterns of autosomal and sex-linked genomic diversity and differentiation, we measured population genetic statistics within and between populations and subspecies of the barn swallow (Hirundo rustica) and performed explicit comparisons between autosomal and Z-linked genomic regions. We first tested for evidence of low Z-linked genetic diversity and high Z-linked population differentiation relative to autosomes, then for evidence that the Z chromosome bears greater ancestry information due to faster lineage sorting. Finally, we investigated geographical clines across hybrid zones for evidence that the Z chromosome is resistant to introgression due to selection against hybrids. We found evidence that the barn swallow mating system, demographic history and linked selection each contribute to low Z-linked diversity and high Z-linked differentiation. While incomplete lineage sorting is rampant across the genome, our results indicate faster sorting of ancestral polymorphism on the Z. Finally, hybrid zone analyses indicate barriers to introgression on the Z chromosome, suggesting that sex-linked traits are important in reproductive isolation, especially in migratory divide regions. Our study highlights how selection, gene flow and demography shape sex-linked genetic diversity and underlines the relevance of the Z chromosome in speciation.
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Affiliation(s)
- Drew R Schield
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Elizabeth S C Scordato
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Department of Biological Sciences, California State Polytechnic University, Pomona, CA, USA
| | - Chris C R Smith
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Javan K Carter
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Sidi Imad Cherkaoui
- Ecole Supérieure de Technologie de Khénifra, Sultan Moulay Slimane University, Béni-Mellal, Morocco
| | - Sundev Gombobaatar
- National University of Mongolia and Mongolian Ornithological Society, Ulaanbaatar, Mongolia
| | - Said Hajib
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | - Saad Hanane
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | - Amanda K Hund
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA
| | | | - Wei Liang
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou, China
| | - Yang Liu
- State Key Laboratory of Biocontrol, School of Ecology, Sun Yat-sen University, Guangzhou, China
| | - Najib Magri
- Water and Forests Department, Forest Research Center, Rabat-Agdal, Morocco
| | | | - Basma Sheta
- Zoology Department, Faculty of Science, Damietta University, New Damietta City, Egypt
| | - Sheela P Turbek
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Matthew R Wilkins
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA.,Collaborative for STEM Education and Outreach, Vanderbilt University, Nashville, TN, USA
| | - Liu Yu
- Key Laboratory for Biodiversity Sciences and Ecological Engineering, Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing, China
| | - Rebecca J Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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18
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Schield DR, Pasquesi GIM, Perry BW, Adams RH, Nikolakis ZL, Westfall AK, Orton RW, Meik JM, Mackessy SP, Castoe TA. Snake Recombination Landscapes Are Concentrated in Functional Regions despite PRDM9. Mol Biol Evol 2021; 37:1272-1294. [PMID: 31926008 DOI: 10.1093/molbev/msaa003] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Meiotic recombination in vertebrates is concentrated in hotspots throughout the genome. The location and stability of hotspots have been linked to the presence or absence of PRDM9, leading to two primary models for hotspot evolution derived from mammals and birds. Species with PRDM9-directed recombination have rapid turnover of hotspots concentrated in intergenic regions (i.e., mammals), whereas hotspots in species lacking PRDM9 are concentrated in functional regions and have greater stability over time (i.e., birds). Snakes possess PRDM9, yet virtually nothing is known about snake recombination. Here, we examine the recombination landscape and test hypotheses about the roles of PRDM9 in rattlesnakes. We find substantial variation in recombination rate within and among snake chromosomes, and positive correlations between recombination rate and gene density, GC content, and genetic diversity. Like mammals, snakes appear to have a functional and active PRDM9, but rather than being directed away from genes, snake hotspots are concentrated in promoters and functional regions-a pattern previously associated only with species that lack a functional PRDM9. Snakes therefore provide a unique example of recombination landscapes in which PRDM9 is functional, yet recombination hotspots are associated with functional genic regions-a combination of features that defy existing paradigms for recombination landscapes in vertebrates. Our findings also provide evidence that high recombination rates are a shared feature of vertebrate microchromosomes. Our results challenge previous assumptions about the adaptive role of PRDM9 and highlight the diversity of recombination landscape features among vertebrate lineages.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | | | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, TX.,Department of Computer & Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL
| | | | | | - Richard W Orton
- Department of Biology, University of Texas at Arlington, Arlington, TX
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, TX
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX
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19
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Nikolakis ZL, Hales NR, Perry BW, Schield DR, Timm LE, Liu Y, Zhong B, Kechris KJ, Carlton EJ, Pollock DD, Castoe TA. Patterns of relatedness and genetic diversity inferred from whole genome sequencing of archival blood fluke miracidia (Schistosoma japonicum). PLoS Negl Trop Dis 2021; 15:e0009020. [PMID: 33406094 PMCID: PMC7815185 DOI: 10.1371/journal.pntd.0009020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 01/19/2021] [Accepted: 11/30/2020] [Indexed: 02/05/2023] Open
Abstract
Genomic approaches hold great promise for resolving unanswered questions about transmission patterns and responses to control efforts for schistosomiasis and other neglected tropical diseases. However, the cost of generating genomic data and the challenges associated with obtaining sufficient DNA from individual schistosome larvae (miracidia) from mammalian hosts have limited the application of genomic data for studying schistosomes and other complex macroparasites. Here, we demonstrate the feasibility of utilizing whole genome amplification and sequencing (WGS) to analyze individual archival miracidia. As an example, we sequenced whole genomes of 22 miracidia from 11 human hosts representing two villages in rural Sichuan, China, and used these data to evaluate patterns of relatedness and genetic diversity. We also down-sampled our dataset to test how lower coverage sequencing could increase the cost effectiveness of WGS while maintaining power to accurately infer relatedness. Collectively, our results illustrate that population-level WGS datasets are attainable for individual miracidia and represent a powerful tool for ultimately providing insight into overall genetic diversity, parasite relatedness, and transmission patterns for better design and evaluation of disease control efforts.
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Affiliation(s)
- Zachary L. Nikolakis
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Nicole R. Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Blair W. Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Drew R. Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
| | - Laura E. Timm
- Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Yang Liu
- Institute of Parasitic Disease, Sichuan Center for Disease Control and Prevention, Chengdu, The People’s Republic of China
| | - Bo Zhong
- Institute of Parasitic Disease, Sichuan Center for Disease Control and Prevention, Chengdu, The People’s Republic of China
| | - Katerina J. Kechris
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado, Anschutz, Aurora, Colorado, United States of America
| | - Elizabeth J. Carlton
- Department of Environmental and Occupational Health, Colorado School of Public Health, University of Colorado, Anschutz, Aurora, Colorado, United States of America
| | - David D. Pollock
- Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Todd A. Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas, United States of America
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20
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Perry BW, Schield DR, Westfall AK, Mackessy SP, Castoe TA. Physiological demands and signaling associated with snake venom production and storage illustrated by transcriptional analyses of venom glands. Sci Rep 2020; 10:18083. [PMID: 33093509 PMCID: PMC7582160 DOI: 10.1038/s41598-020-75048-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 10/09/2020] [Indexed: 01/30/2023] Open
Abstract
Despite the extensive body of research on snake venom, many facets of snake venom systems, such as the physiology and regulation of the venom gland itself, remain virtually unstudied. Here, we use time series gene expression analyses of the rattlesnake venom gland in comparison with several non-venom tissues to characterize physiological and cellular processes associated with venom production and to highlight key distinctions of venom gland cellular and physiological function. We find consistent evidence for activation of stress response pathways in the venom gland, suggesting that mitigation of cellular stress is a crucial component of venom production. Additionally, we demonstrate evidence for an unappreciated degree of cellular and secretory activity in the steady state venom gland relative to other secretory tissues and identify vacuolar ATPases as the likely mechanisms driving acidification of the venom gland lumen during venom production and storage.
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Affiliation(s)
- Blair W Perry
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr., Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr., Arlington, TX, 76019, USA.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, 80309, USA
| | - Aundrea K Westfall
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr., Arlington, TX, 76019, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA
| | - Todd A Castoe
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr., Arlington, TX, 76019, USA.
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21
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Card DC, Adams RH, Schield DR, Perry BW, Corbin AB, Pasquesi GIM, Row K, Van Kleeck MJ, Daza JM, Booth W, Montgomery CE, Boback SM, Castoe TA. Genomic Basis of Convergent Island Phenotypes in Boa Constrictors. Genome Biol Evol 2020; 11:3123-3143. [PMID: 31642474 PMCID: PMC6836717 DOI: 10.1093/gbe/evz226] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2019] [Indexed: 12/14/2022] Open
Abstract
Convergent evolution is often documented in organisms inhabiting isolated environments with distinct ecological conditions and similar selective regimes. Several Central America islands harbor dwarf Boa populations that are characterized by distinct differences in growth, mass, and craniofacial morphology, which are linked to the shared arboreal and feast-famine ecology of these island populations. Using high-density RADseq data, we inferred three dwarf island populations with independent origins and demonstrate that selection, along with genetic drift, has produced both divergent and convergent molecular evolution across island populations. Leveraging whole-genome resequencing data for 20 individuals and a newly annotated Boa genome, we identify four genes with evidence of phenotypically relevant protein-coding variation that differentiate island and mainland populations. The known roles of these genes involved in body growth (PTPRS, DMGDH, and ARSB), circulating fat and cholesterol levels (MYLIP), and craniofacial development (DMGDH and ARSB) in mammals link patterns of molecular evolution with the unique phenotypes of these island forms. Our results provide an important genome-wide example for quantifying expectations of selection and convergence in closely related populations. We also find evidence at several genomic loci that selection may be a prominent force of evolutionary change—even for small island populations for which drift is predicted to dominate. Overall, while phenotypically convergent island populations show relatively few loci under strong selection, infrequent patterns of molecular convergence are still apparent and implicate genes with strong connections to convergent phenotypes.
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Affiliation(s)
- Daren C Card
- Department of Biology, University of Texas Arlington.,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts.,Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts
| | | | | | - Blair W Perry
- Department of Biology, University of Texas Arlington
| | | | | | | | | | - Juan M Daza
- Grupo Herpetológico de Antioquia, Instituto de Biología, Universidad de Antioquia, Medellín, Colombia
| | - Warren Booth
- Department of Biological Science, University of Tulsa, Oklahoma
| | | | - Scott M Boback
- Department of Biology, Dickinson College, Carlisle, Pennsylvania
| | - Todd A Castoe
- Department of Biology, University of Texas Arlington
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22
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Watson JA, Spencer CL, Schield DR, Butler BO, Smith LL, Flores-Villela O, Campbell JA, Mackessy SP, Castoe TA, Meik JM. Geographic variation in morphology in the Mohave Rattlesnake (Crotalus scutulatus Kennicott 1861) (Serpentes: Viperidae): implications for species boundaries. Zootaxa 2019; 4683:zootaxa.4683.1.7. [PMID: 31715939 DOI: 10.11646/zootaxa.4683.1.7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Indexed: 11/04/2022]
Abstract
The Mohave Rattlesnake (Crotalus scutulatus) is a highly venomous pitviper inhabiting the arid interior deserts, grasslands, and savannas of western North America. Currently two subspecies are recognized: the Northern Mohave Rattlesnake (C. s. scutulatus) ranging from southern California to the southern Central Mexican Plateau, and the Huamantla Rattlesnake (C. s. salvini) from the region of Tlaxcala, Veracruz, and Puebla in south-central Mexico. Although recent studies have demonstrated extensive geographic variation in venom composition and cryptic genetic diversity in this species, no modern studies have focused on geographic variation in morphology. Here we analyzed a series of qualitative, meristic, and morphometric traits from 347 specimens of C. scutulatus and show that this species is phenotypically cohesive without discrete subgroups, and that morphology follows a continuous cline in primarily color pattern and meristic traits across the major axis of its expansive distribution. Interpreted in the context of previously published molecular evidence, our morphological analyses suggest that multiple episodes of isolation and secondary contact among metapopulations during the Pleistocene were sufficient to produce distinctive genetic populations, which have since experienced gene flow to produce clinal variation in phenotypes without discrete or diagnosable distinctions among these original populations. For taxonomic purposes, we recommend that C. scutulatus be retained as a single species, although it is possible that C. s. salvini, which is morphologically the most distinctive population, could represent a peripheral isolate in the initial stages of speciation.
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Affiliation(s)
- Jessica A Watson
- Department of Biological Sciences, Tarleton State University, 1333 W. Washington Street, Stephenville, Texas, 76402 USA..
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23
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Adams RH, Schield DR, Card DC, Corbin A, Castoe TA. ThetaMater: Bayesian estimation of population size parameter θ from genomic data. Bioinformatics 2019; 34:1072-1073. [PMID: 29194472 DOI: 10.1093/bioinformatics/btx733] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 11/27/2017] [Indexed: 11/14/2022] Open
Abstract
Summary We describe ThetaMater, an open source R package comprising a suite of functions for efficient and scalable Bayesian estimation of the population size parameter θ from genomic data. Availability and implementation ThetaMater is available at GitHub (https://github.com/radamsRHA/ThetaMater). Contact todd.castoe@uta.edu. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Richard H Adams
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Drew R Schield
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Daren C Card
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Andrew Corbin
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Todd A Castoe
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
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24
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Perry BW, Andrew AL, Mostafa Kamal AH, Card DC, Schield DR, Pasquesi GIM, Pellegrino MW, Mackessy SP, Chowdhury SM, Secor SM, Castoe TA. Multi-species comparisons of snakes identify coordinated signalling networks underlying post-feeding intestinal regeneration. Proc Biol Sci 2019; 286:20190910. [PMID: 31288694 DOI: 10.1098/rspb.2019.0910] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Several snake species that feed infrequently in nature have evolved the ability to massively upregulate intestinal form and function with each meal. While fasting, these snakes downregulate intestinal form and function, and upon feeding restore intestinal structure and function through major increases in cell growth and proliferation, metabolism and upregulation of digestive function. Previous studies have identified changes in gene expression that underlie this regenerative growth of the python intestine, but the unique features that differentiate this extreme regenerative growth from non-regenerative post-feeding responses exhibited by snakes that feed more frequently remain unclear. Here, we leveraged variation in regenerative capacity across three snake species-two distantly related lineages ( Crotalus and Python) that experience regenerative growth, and one ( Nerodia) that does not-to infer molecular mechanisms underlying intestinal regeneration using transcriptomic and proteomic approaches. Using a comparative approach, we identify a suite of growth, stress response and DNA damage response signalling pathways with inferred activity specifically in regenerating species, and propose a hypothesis model of interactivity between these pathways that may drive regenerative intestinal growth in snakes.
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Affiliation(s)
- Blair W Perry
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Audra L Andrew
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Abu Hena Mostafa Kamal
- 2 Department of Chemistry and Biochemistry, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Daren C Card
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Drew R Schield
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Giulia I M Pasquesi
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Mark W Pellegrino
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Stephen P Mackessy
- 3 School of Biological Sciences, University of Northern Colorado , 501 20th Street, Greeley, CO 80639 , USA
| | - Saiful M Chowdhury
- 2 Department of Chemistry and Biochemistry, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
| | - Stephen M Secor
- 4 Department of Biological Sciences, University of Alabama , Box 870344, Tuscaloosa, AL 35487 , USA
| | - Todd A Castoe
- 1 Department of Biology, The University of Texas Arlington , 501 South Nedderman Drive, Arlington, TX 76019 , USA
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25
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Schield DR, Perry BW, Adams RH, Card DC, Jezkova T, Pasquesi GIM, Nikolakis ZL, Row K, Meik JM, Smith CF, Mackessy SP, Castoe TA. Allopatric divergence and secondary contact with gene flow: a recurring theme in rattlesnake speciation. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz077] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
The study of recently diverged lineages whose geographical ranges come into contact can provide insight into the early stages of speciation and the potential roles of reproductive isolation in generating and maintaining species. Such insight can also be important for understanding the strategies and challenges for delimiting species within recently diverged species complexes. Here, we use mitochondrial and nuclear genetic data to study population structure, gene flow and demographic history across a geographically widespread rattlesnake clade, the western rattlesnake species complex (Crotalus cerberus, Crotalus viridis, Crotalus oreganus and relatives), which contains multiple lineages with ranges that overlap geographically or contact one another. We find evidence that the evolutionary history of this group does not conform to a bifurcating tree model and that pervasive gene flow has broadly influenced patterns of present-day genetic diversity. Our results suggest that lineage diversity has been shaped largely by drift and divergent selection in isolation, followed by secondary contact, in which reproductive isolating mechanisms appear weak and insufficient to prevent introgression, even between anciently diverged lineages. The complexity of divergence and secondary contact with gene flow among lineages also provides new context for why delimiting species within this complex has been difficult and contentious historically.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Museum of Comparative Zoology, Harvard University, Cambridge, MA, USA
| | - Tereza Jezkova
- Department of Biology, Miami University of Ohio, Oxford, OH, USA
| | | | | | - Kristopher Row
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, TX, USA
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, CO, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
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26
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27
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Schield DR, Card DC, Hales NR, Perry BW, Pasquesi GM, Blackmon H, Adams RH, Corbin AB, Smith CF, Ramesh B, Demuth JP, Betrán E, Tollis M, Meik JM, Mackessy SP, Castoe TA. The origins and evolution of chromosomes, dosage compensation, and mechanisms underlying venom regulation in snakes. Genome Res 2019; 29:590-601. [PMID: 30898880 PMCID: PMC6442385 DOI: 10.1101/gr.240952.118] [Citation(s) in RCA: 91] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 02/15/2019] [Indexed: 01/28/2023]
Abstract
Here we use a chromosome-level genome assembly of a prairie rattlesnake (Crotalus viridis), together with Hi-C, RNA-seq, and whole-genome resequencing data, to study key features of genome biology and evolution in reptiles. We identify the rattlesnake Z Chromosome, including the recombining pseudoautosomal region, and find evidence for partial dosage compensation driven by an evolutionary accumulation of a female-biased up-regulation mechanism. Comparative analyses with other amniotes provide new insight into the origins, structure, and function of reptile microchromosomes, which we demonstrate have markedly different structure and function compared to macrochromosomes. Snake microchromosomes are also enriched for venom genes, which we show have evolved through multiple tandem duplication events in multiple gene families. By overlaying chromatin structure information and gene expression data, we find evidence for venom gene-specific chromatin contact domains and identify how chromatin structure guides precise expression of multiple venom gene families. Further, we find evidence for venom gland-specific transcription factor activity and characterize a complement of mechanisms underlying venom production and regulation. Our findings reveal novel and fundamental features of reptile genome biology, provide insight into the regulation of snake venom, and broadly highlight the biological insight enabled by chromosome-level genome assemblies.
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Affiliation(s)
- Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Giulia M Pasquesi
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Heath Blackmon
- Department of Biology, Texas A&M University, College Station, Texas 77843, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Cara F Smith
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Balan Ramesh
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Jeffery P Demuth
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Esther Betrán
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
| | - Marc Tollis
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
| | - Jesse M Meik
- Department of Biological Sciences, Tarleton State University, Stephenville, Texas 76402, USA
| | - Stephen P Mackessy
- School of Biological Sciences, University of Northern Colorado, Greeley, Colorado 80639, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas 76010, USA
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28
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Card DC, Schield DR, Castoe TA. Plasticity and local adaptation explain lizard cold tolerance. Mol Ecol 2019; 27:2173-2175. [PMID: 29737602 DOI: 10.1111/mec.14575] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 11/29/2022]
Abstract
How does climate variation limit the range of species and what does it take for species to colonize new regions? In this issue of Molecular Ecology, Campbell-Staton et al. () address these broad questions by investigating cold tolerance adaptation in the green anole lizard (Anolis carolinensis) across a latitudinal transect. By integrating physiological data, gene expression data and acclimation experiments, the authors disentangle the mechanisms underlying cold adaptation. They first establish that cold tolerance adaptation in Anolis lizards follows the predictions of the oxygen- and capacity-limited thermal tolerance hypothesis, which states that organisms are limited by temperature thresholds at which oxygen supply cannot meet demand. They then explore the drivers of cold tolerance at a finer scale, finding evidence that northern populations are adapted to cooler thermal regimes and that both phenotypic plasticity and heritable genetic variation contribute to cold tolerance. The integration of physiological and gene expression data further highlights the varied mechanisms that drive cold tolerance adaptation in Anolis lizards, including both supply-side and demand-side adaptations that improve oxygen economy. Altogether, their work provides new insight into the physiological and genetic mechanisms underlying adaptation to new climatic niches and demonstrates that cold tolerance in northern lizard populations is achieved through the synergy of physiological plasticity and local genetic adaptation for thermal performance.
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Affiliation(s)
- Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, Texas
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, Texas
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, Texas
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29
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Card DC, Perry BW, Adams RH, Schield DR, Young AS, Andrew AL, Jezkova T, Pasquesi GI, Hales NR, Walsh MR, Rochford MR, Mazzotti FJ, Hart KM, Hunter ME, Castoe TA. Novel ecological and climatic conditions drive rapid adaptation in invasive Florida Burmese pythons. Mol Ecol 2018; 27:4744-4757. [DOI: 10.1111/mec.14885] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/24/2018] [Accepted: 09/14/2018] [Indexed: 12/30/2022]
Affiliation(s)
- Daren C. Card
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Blair W. Perry
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Richard H. Adams
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Drew R. Schield
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Acacia S. Young
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Audra L. Andrew
- Department of Biology The University of Texas at Arlington Arlington Texas
| | | | | | - Nicole R. Hales
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Matthew R. Walsh
- Department of Biology The University of Texas at Arlington Arlington Texas
| | - Michael R. Rochford
- Fort Lauderdale Research & Education Center University of Florida Fort Lauderdale Florida
| | - Frank J. Mazzotti
- Fort Lauderdale Research & Education Center University of Florida Fort Lauderdale Florida
| | - Kristen M. Hart
- U. S. Geological Survey Wetland and Aquatic Research Center Davie Florida
| | - Margaret E. Hunter
- U. S. Geological Survey Wetland and Aquatic Research Center Gainesville Florida
| | - Todd A. Castoe
- Department of Biology The University of Texas at Arlington Arlington Texas
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30
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Schield DR, Adams RH, Card DC, Corbin AB, Jezkova T, Hales NR, Meik JM, Perry BW, Spencer CL, Smith LL, García GC, Bouzid NM, Strickland JL, Parkinson CL, Borja M, Castañeda-Gaytán G, Bryson RW, Flores-Villela OA, Mackessy SP, Castoe TA. Cryptic genetic diversity, population structure, and gene flow in the Mojave rattlesnake (Crotalus scutulatus). Mol Phylogenet Evol 2018; 127:669-681. [DOI: 10.1016/j.ympev.2018.06.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 05/30/2018] [Accepted: 06/06/2018] [Indexed: 10/28/2022]
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31
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Perry BW, Card DC, McGlothlin JW, Pasquesi GIM, Adams RH, Schield DR, Hales NR, Corbin AB, Demuth JP, Hoffmann FG, Vandewege MW, Schott RK, Bhattacharyya N, Chang BSW, Casewell NR, Whiteley G, Reyes-Velasco J, Mackessy SP, Gamble T, Storey KB, Biggar KK, Passow CN, Kuo CH, McGaugh SE, Bronikowski AM, de Koning APJ, Edwards SV, Pfrender ME, Minx P, Brodie ED, Brodie ED, Warren WC, Castoe TA. Molecular Adaptations for Sensing and Securing Prey and Insight into Amniote Genome Diversity from the Garter Snake Genome. Genome Biol Evol 2018; 10:2110-2129. [PMID: 30060036 PMCID: PMC6110522 DOI: 10.1093/gbe/evy157] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/26/2018] [Indexed: 12/26/2022] Open
Abstract
Colubridae represents the most phenotypically diverse and speciose family of snakes, yet no well-assembled and annotated genome exists for this lineage. Here, we report and analyze the genome of the garter snake, Thamnophis sirtalis, a colubrid snake that is an important model species for research in evolutionary biology, physiology, genomics, behavior, and the evolution of toxin resistance. Using the garter snake genome, we show how snakes have evolved numerous adaptations for sensing and securing prey, and identify features of snake genome structure that provide insight into the evolution of amniote genomes. Analyses of the garter snake and other squamate reptile genomes highlight shifts in repeat element abundance and expansion within snakes, uncover evidence of genes under positive selection, and provide revised neutral substitution rate estimates for squamates. Our identification of Z and W sex chromosome-specific scaffolds provides evidence for multiple origins of sex chromosome systems in snakes and demonstrates the value of this genome for studying sex chromosome evolution. Analysis of gene duplication and loss in visual and olfactory gene families supports a dim-light ancestral condition in snakes and indicates that olfactory receptor repertoires underwent an expansion early in snake evolution. Additionally, we provide some of the first links between secreted venom proteins, the genes that encode them, and their evolutionary origins in a rear-fanged colubrid snake, together with new genomic insight into the coevolutionary arms race between garter snakes and highly toxic newt prey that led to toxin resistance in garter snakes.
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Affiliation(s)
- Blair W Perry
- Department of Biology, University of Texas at Arlington, Arlington
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington
| | - Joel W McGlothlin
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia
| | | | - Richard H Adams
- Department of Biology, University of Texas at Arlington, Arlington
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington
| | - Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, Arlington
| | - Jeffery P Demuth
- Department of Biology, University of Texas at Arlington, Arlington
| | - Federico G Hoffmann
- Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology, Mississippi State University, Mississippi State.,Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Starkville
| | - Michael W Vandewege
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University
| | - Ryan K Schott
- Department of Ecology and Evolutionary Biology, Department of Cell and Systems Biology, Centre for the Analysis of Genome Evolution & Function, University of Toronto, Ontario, Canada.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia
| | - Nihar Bhattacharyya
- Department of Cell and Systems Biology, University of Toronto, Ontario, Canada
| | - Belinda S W Chang
- Department of Ecology and Evolutionary Biology, Department of Cell and Systems Biology, Centre for the Analysis of Genome Evolution & Function, University of Toronto, Ontario, Canada
| | - Nicholas R Casewell
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Gareth Whiteley
- Alistair Reid Venom Research Unit, Parasitology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
| | - Jacobo Reyes-Velasco
- Department of Biology, University of Texas at Arlington, Arlington.,Department of Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | | | - Tony Gamble
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA.,Bell Museum of Natural History, University of Minnesota, Saint Paul, MN, USA
| | - Kenneth B Storey
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | - Kyle K Biggar
- Institute of Biochemistry, Carleton University, Ottawa, Ontario, Canada
| | | | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | | | - Anne M Bronikowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University
| | - A P Jason de Koning
- Department of Biochemistry and Molecular Biology, Department of Medical Genetics, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University
| | - Michael E Pfrender
- Department of Biological Sciences and Environmental Change Initiative, University of Notre Dame
| | - Patrick Minx
- The McDonnell Genome Institute, Washington University School of Medicine, St. Louis
| | | | | | - Wesley C Warren
- The McDonnell Genome Institute, Washington University School of Medicine, St. Louis
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington
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Pasquesi GIM, Adams RH, Card DC, Schield DR, Corbin AB, Perry BW, Reyes-Velasco J, Ruggiero RP, Vandewege MW, Shortt JA, Castoe TA. Squamate reptiles challenge paradigms of genomic repeat element evolution set by birds and mammals. Nat Commun 2018; 9:2774. [PMID: 30018307 PMCID: PMC6050309 DOI: 10.1038/s41467-018-05279-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 06/25/2018] [Indexed: 12/14/2022] Open
Abstract
Broad paradigms of vertebrate genomic repeat element evolution have been largely shaped by analyses of mammalian and avian genomes. Here, based on analyses of genomes sequenced from over 60 squamate reptiles (lizards and snakes), we show that patterns of genomic repeat landscape evolution in squamates challenge such paradigms. Despite low variance in genome size, squamate genomes exhibit surprisingly high variation among species in abundance (ca. 25–73% of the genome) and composition of identifiable repeat elements. We also demonstrate that snake genomes have experienced microsatellite seeding by transposable elements at a scale unparalleled among eukaryotes, leading to some snake genomes containing the highest microsatellite content of any known eukaryote. Our analyses of transposable element evolution across squamates also suggest that lineage-specific variation in mechanisms of transposable element activity and silencing, rather than variation in species-specific demography, may play a dominant role in driving variation in repeat element landscapes across squamate phylogeny. Large-scale patterns of genomic repeat element evolution have been studied mainly in birds and mammals. Here, the authors analyze the genomes of over 60 squamate reptiles and show high variation in repeat elements compared to mammals and birds, and particularly high microsatellite seeding in snakes.
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Affiliation(s)
- Giulia I M Pasquesi
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Richard H Adams
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Andrew B Corbin
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA
| | - Jacobo Reyes-Velasco
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.,Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Robert P Ruggiero
- Department of Biology, New York University Abu Dhabi, Saadiyat Island, United Arab Emirates
| | - Michael W Vandewege
- Department of Biology, Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, 19122, USA
| | - Jonathan A Shortt
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, 501S. Nedderman Drive, Arlington, TX, 76019, USA.
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Adams RH, Schield DR, Card DC, Castoe TA. Assessing the Impacts of Positive Selection on Coalescent-Based Species Tree Estimation and Species Delimitation. Syst Biol 2018; 67:1076-1090. [DOI: 10.1093/sysbio/syy034] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 05/05/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Richard H Adams
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Dr., Arlington, TX 76019, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Dr., Arlington, TX 76019, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Dr., Arlington, TX 76019, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, 501 S. Nedderman Dr., Arlington, TX 76019, USA
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Adams RH, Schield DR, Card DC, Blackmon H, Castoe TA. GppFst: genomic posterior predictive simulations of FST and dXY for identifying outlier loci from population genomic data. Bioinformatics 2018; 33:1414-1415. [PMID: 28453670 DOI: 10.1093/bioinformatics/btw795] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Accepted: 12/13/2016] [Indexed: 11/12/2022] Open
Abstract
Summary We introduce GppFst, an open source R package that generates posterior predictive distributions of FST and dx under a neutral coalescent model to identify putative targets of selection from genomic data. Availability and Implementation GppFst is available at ( https://github.com/radamsRHA/GppFst ). Contact todd.castoe@uta.edu. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Richard H Adams
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Drew R Schield
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Daren C Card
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Heath Blackmon
- Department of Ecology, Evolution & Behavior, University of Minnesota, Saint Paul, MN 55108, USA
| | - Todd A Castoe
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
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Hales NR, Schield DR, Andrew AL, Card DC, Walsh MR, Castoe TA. Contrasting gene expression programs correspond with predator-induced phenotypic plasticity within and across generations in Daphnia. Mol Ecol 2017. [PMID: 28628257 DOI: 10.1111/mec.14213] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Research has shown that a change in environmental conditions can alter the expression of traits during development (i.e., "within-generation phenotypic plasticity") as well as induce heritable phenotypic responses that persist for multiple generations (i.e., "transgenerational plasticity", TGP). It has long been assumed that shifts in gene expression are tightly linked to observed trait responses at the phenotypic level. Yet, the manner in which organisms couple within- and TGP at the molecular level is unclear. Here we tested the influence of fish predator chemical cues on patterns of gene expression within- and across generations using a clone of Daphnia ambigua that is known to exhibit strong TGP but weak within-generation plasticity. Daphnia were reared in the presence of predator cues in generation 1, and shifts in gene expression were tracked across two additional asexual experimental generations that lacked exposure to predator cues. Initial exposure to predator cues in generation 1 was linked to ~50 responsive genes, but such shifts were 3-4× larger in later generations. Differentially expressed genes included those involved in reproduction, exoskeleton structure and digestion; major shifts in expression of genes encoding ribosomal proteins were also identified. Furthermore, shifts within the first-generation and transgenerational shifts in gene expression were largely distinct in terms of the genes that were differentially expressed. Such results argue that the gene expression programmes involved in within- vs. transgeneration plasticity are fundamentally different. Our study provides new key insights into the plasticity of gene expression and how it relates to phenotypic plasticity in nature.
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Affiliation(s)
- Nicole R Hales
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Drew R Schield
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Audra L Andrew
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Daren C Card
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Matthew R Walsh
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
| | - Todd A Castoe
- Department of Biology, University of Texas at Arlington, Arlington, TX, USA
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Gamble T, Castoe TA, Nielsen SV, Banks JL, Card DC, Schield DR, Schuett GW, Booth W. The Discovery of XY Sex Chromosomes in a Boa and Python. Curr Biol 2017; 27:2148-2153.e4. [DOI: 10.1016/j.cub.2017.06.010] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 04/21/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022]
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Andrew AL, Perry BW, Card DC, Schield DR, Ruggiero RP, McGaugh SE, Choudhary A, Secor SM, Castoe TA. Growth and stress response mechanisms underlying post-feeding regenerative organ growth in the Burmese python. BMC Genomics 2017; 18:338. [PMID: 28464824 PMCID: PMC5412052 DOI: 10.1186/s12864-017-3743-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 04/27/2017] [Indexed: 12/26/2022] Open
Abstract
Background Previous studies examining post-feeding organ regeneration in the Burmese python (Python molurus bivittatus) have identified thousands of genes that are significantly differentially regulated during this process. However, substantial gaps remain in our understanding of coherent mechanisms and specific growth pathways that underlie these rapid and extensive shifts in organ form and function. Here we addressed these gaps by comparing gene expression in the Burmese python heart, liver, kidney, and small intestine across pre- and post-feeding time points (fasted, one day post-feeding, and four days post-feeding), and by conducting detailed analyses of molecular pathways and predictions of upstream regulatory molecules across these organ systems. Results Identified enriched canonical pathways and upstream regulators indicate that while downstream transcriptional responses are fairly tissue specific, a suite of core pathways and upstream regulator molecules are shared among responsive tissues. Pathways such as mTOR signaling, PPAR/LXR/RXR signaling, and NRF2-mediated oxidative stress response are significantly differentially regulated in multiple tissues, indicative of cell growth and proliferation along with coordinated cell-protective stress responses. Upstream regulatory molecule analyses identify multiple growth factors, kinase receptors, and transmembrane receptors, both within individual organs and across separate tissues. Downstream transcription factors MYC and SREBF are induced in all tissues. Conclusions These results suggest that largely divergent patterns of post-feeding gene regulation across tissues are mediated by a core set of higher-level signaling molecules. Consistent enrichment of the NRF2-mediated oxidative stress response indicates this pathway may be particularly important in mediating cellular stress during such extreme regenerative growth. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3743-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Audra L Andrew
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr, Arlington, TX, 76019, USA
| | - Blair W Perry
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr, Arlington, TX, 76019, USA
| | - Daren C Card
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr, Arlington, TX, 76019, USA
| | - Drew R Schield
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr, Arlington, TX, 76019, USA
| | - Robert P Ruggiero
- Department of Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Suzanne E McGaugh
- Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, 55108, USA
| | - Amit Choudhary
- Harvard Medical School, Renal Division, Brigham and Woman's Hospital, Cambridge, MA, 02142, USA.,Center for the Science of Therapeutics, Broad Institute, Cambridge, MA, 02142, USA
| | - Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, Box 870344, USA
| | - Todd A Castoe
- Department of Biology, The University of Texas Arlington, 501 S. Nedderman Dr, Arlington, TX, 76019, USA.
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Schield DR, Adams RH, Card DC, Perry BW, Pasquesi GM, Jezkova T, Portik DM, Andrew AL, Spencer CL, Sanchez EE, Fujita MK, Mackessy SP, Castoe TA. Insight into the roles of selection in speciation from genomic patterns of divergence and introgression in secondary contact in venomous rattlesnakes. Ecol Evol 2017; 7:3951-3966. [PMID: 28616190 PMCID: PMC5468163 DOI: 10.1002/ece3.2996] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 03/21/2017] [Indexed: 01/03/2023] Open
Abstract
Investigating secondary contact of historically isolated lineages can provide insight into how selection and drift influence genomic divergence and admixture. Here, we studied the genomic landscape of divergence and introgression following secondary contact between lineages of the Western Diamondback Rattlesnake (Crotalus atrox) to determine whether genomic regions under selection in allopatry also contribute to reproductive isolation during introgression. We used thousands of nuclear loci to study genomic differentiation between two lineages that have experienced recent secondary contact following isolation, and incorporated sampling from a zone of secondary contact to identify loci that are resistant to gene flow in hybrids. Comparisons of patterns of divergence and introgression revealed a positive relationship between allelic differentiation and resistance to introgression across the genome, and greater‐than‐expected overlap between genes linked to lineage‐specific divergence and loci that resist introgression. Genes linked to putatively selected markers were related to prominent aspects of rattlesnake biology that differ between populations of Western Diamondback rattlesnakes (i.e., venom and reproductive phenotypes). We also found evidence for selection against introgression of genes that may contribute to cytonuclear incompatibility, consistent with previously observed biased patterns of nuclear and mitochondrial alleles suggestive of partial reproductive isolation due to cytonuclear incompatibilities. Our results provide a genome‐scale perspective on the relationships between divergence and introgression in secondary contact that is relevant for understanding the roles of selection in maintaining partial isolation of lineages, causing admixing lineages to not completely homogenize.
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Affiliation(s)
- Drew R Schield
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Richard H Adams
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Daren C Card
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Blair W Perry
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Giulia M Pasquesi
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Tereza Jezkova
- Department of Ecology and Evolutionary Biology University of Arizona Tucson AZ USA
| | - Daniel M Portik
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Audra L Andrew
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Carol L Spencer
- Museum of Vertebrate Zoology University of California Berkeley CA USA
| | - Elda E Sanchez
- National Natural Toxins Research Center and Department of Chemistry Texas A&M University Kingsville Kingsville TX USA
| | - Matthew K Fujita
- Department of Biology The University of Texas at Arlington Arlington TX USA
| | - Stephen P Mackessy
- School of Biological Sciences University of Northern Colorado Greeley CO USA
| | - Todd A Castoe
- Department of Biology The University of Texas at Arlington Arlington TX USA
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Shortt JA, Card DC, Schield DR, Liu Y, Zhong B, Castoe TA, Carlton EJ, Pollock DD. Whole Genome Amplification and Reduced-Representation Genome Sequencing of Schistosoma japonicum Miracidia. PLoS Negl Trop Dis 2017; 11:e0005292. [PMID: 28107347 PMCID: PMC5287463 DOI: 10.1371/journal.pntd.0005292] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 02/01/2017] [Accepted: 12/29/2016] [Indexed: 11/18/2022] Open
Abstract
Background In areas where schistosomiasis control programs have been implemented, morbidity and prevalence have been greatly reduced. However, to sustain these reductions and move towards interruption of transmission, new tools for disease surveillance are needed. Genomic methods have the potential to help trace the sources of new infections, and allow us to monitor drug resistance. Large-scale genotyping efforts for schistosome species have been hindered by cost, limited numbers of established target loci, and the small amount of DNA obtained from miracidia, the life stage most readily acquired from humans. Here, we present a method using next generation sequencing to provide high-resolution genomic data from S. japonicum for population-based studies. Methodology/Principal Findings We applied whole genome amplification followed by double digest restriction site associated DNA sequencing (ddRADseq) to individual S. japonicum miracidia preserved on Whatman FTA cards. We found that we could effectively and consistently survey hundreds of thousands of variants from 10,000 to 30,000 loci from archived miracidia as old as six years. An analysis of variation from eight miracidia obtained from three hosts in two villages in Sichuan showed clear population structuring by village and host even within this limited sample. Conclusions/Significance This high-resolution sequencing approach yields three orders of magnitude more information than microsatellite genotyping methods that have been employed over the last decade, creating the potential to answer detailed questions about the sources of human infections and to monitor drug resistance. Costs per sample range from $50-$200, depending on the amount of sequence information desired, and we expect these costs can be reduced further given continued reductions in sequencing costs, improvement of protocols, and parallelization. This approach provides new promise for using modern genome-scale sampling to S. japonicum surveillance, and could be applied to other schistosome species and other parasitic helminthes. Schistosomiasis is a devastating tropical disease that affects more than 200 million people worldwide. Over the past several decades, transmission control strategies implemented in China have reduced the prevalence and morbidity of Schistosoma japonicum in many areas. Infections still persist, however, and it is therefore of great interest to determine the sources of recurring infections. Genetic analysis is a promising means to achieve this. Towards this aim, we conducted a pilot study to assess the feasibility of using high-throughput sequencing to assess the geographic distribution of schistosome genetic variants. Because DNA yields from miracidia, the most easily accessible life stage, are insufficient for high throughput sequencing, we first employed whole genome amplification to obtain sufficient quantities of DNA. We then employed a technique that reproducibly sequences the same fraction of a genome across numerous samples. We successfully sequenced 6-year old S. japonicum samples from Sichuan Province, China, easily and economically identifying tens of thousands of variable loci, a sufficient number to discriminate fine-scale population structure. Further population sampling will help answer important questions concerning the persistence of infections, the sources of new infections, and whether parasite populations have undergone incipient evolution of drug resistance.
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Affiliation(s)
- Jonathan A. Shortt
- Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, United States of America
| | - Daren C. Card
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Drew R. Schield
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Yang Liu
- Institute of Parasitic Disease, Sichuan Center for Disease Control and Prevention, Chengdu, The People’s Republic of China
| | - Bo Zhong
- Institute of Parasitic Disease, Sichuan Center for Disease Control and Prevention, Chengdu, The People’s Republic of China
| | - Todd A. Castoe
- Department of Biology, University of Texas Arlington, Arlington, TX, United States of America
| | - Elizabeth J. Carlton
- Department of Environmental and Occupational Health, University of Colorado, Colorado School of Public Health, Aurora, CO, United States of America
| | - David D. Pollock
- Department of Biochemistry & Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, United States of America
- * E-mail:
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Streicher JW, McEntee JP, Drzich LC, Card DC, Schield DR, Smart U, Parkinson CL, Jezkova T, Smith EN, Castoe TA. Genetic surfing, not allopatric divergence, explains spatial sorting of mitochondrial haplotypes in venomous coralsnakes. Evolution 2016; 70:1435-49. [DOI: 10.1111/evo.12967] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 04/30/2016] [Accepted: 05/16/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Jeffrey W. Streicher
- Department of Life Sciences The Natural History Museum London United Kingdom
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Jay P. McEntee
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
- Department of Biology University of Florida Gainesville Florida
| | - Laura C. Drzich
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Daren C. Card
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Drew R. Schield
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Utpal Smart
- Department of Biology University of Texas at Arlington Arlington Texas
| | | | - Tereza Jezkova
- Department of Ecology and Evolutionary Biology University of Arizona Tucson Arizona
| | - Eric N. Smith
- Department of Biology University of Texas at Arlington Arlington Texas
| | - Todd A. Castoe
- Department of Biology University of Texas at Arlington Arlington Texas
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Card DC, Schield DR, Adams RH, Corbin AB, Perry BW, Andrew AL, Pasquesi GIM, Smith EN, Jezkova T, Boback SM, Booth W, Castoe TA. Phylogeographic and population genetic analyses reveal multiple species of Boa and independent origins of insular dwarfism. Mol Phylogenet Evol 2016; 102:104-16. [PMID: 27241629 DOI: 10.1016/j.ympev.2016.05.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2015] [Revised: 05/05/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
Abstract
Boa is a Neotropical genus of snakes historically recognized as monotypic despite its expansive distribution. The distinct morphological traits and color patterns exhibited by these snakes, together with the wide diversity of ecosystems they inhabit, collectively suggest that the genus may represent multiple species. Morphological variation within Boa also includes instances of dwarfism observed in multiple offshore island populations. Despite this substantial diversity, the systematics of the genus Boa has received little attention until very recently. In this study we examined the genetic structure and phylogenetic relationships of Boa populations using mitochondrial sequences and genome-wide SNP data obtained from RADseq. We analyzed these data at multiple geographic scales using a combination of phylogenetic inference (including coalescent-based species delimitation) and population genetic analyses. We identified extensive population structure across the range of the genus Boa and multiple lines of evidence for three widely-distributed clades roughly corresponding with the three primary land masses of the Western Hemisphere. We also find both mitochondrial and nuclear support for independent origins and parallel evolution of dwarfism on offshore island clusters in Belize and Cayos Cochinos Menor, Honduras.
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Affiliation(s)
- Daren C Card
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Drew R Schield
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Richard H Adams
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Andrew B Corbin
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Blair W Perry
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Audra L Andrew
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Giulia I M Pasquesi
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Eric N Smith
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Tereza Jezkova
- Department of Ecology & Evolutionary Biology, University of Arizona, P.O. Box 210088, Tucson, AZ 85721, USA
| | - Scott M Boback
- Department of Biology, P.O. Box 1773, Dickinson College, Carlisle, PA 17013, USA
| | - Warren Booth
- Department of Biological Science, 800 South Tucker Drive, University of Tulsa, Tulsa, OK 74104, USA
| | - Todd A Castoe
- Department of Biology, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA.
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42
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Adams RH, Blackmon H, Reyes-Velasco J, Schield DR, Card DC, Andrew AL, Waynewood N, Castoe TA. Microsatellite landscape evolutionary dynamics across 450 million years of vertebrate genome evolution. Genome 2016; 59:295-310. [PMID: 27064176 DOI: 10.1139/gen-2015-0124] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The evolutionary dynamics of simple sequence repeats (SSRs or microsatellites) across the vertebrate tree of life remain largely undocumented and poorly understood. In this study, we analyzed patterns of genomic microsatellite abundance and evolution across 71 vertebrate genomes. The highest abundances of microsatellites exist in the genomes of ray-finned fishes, squamate reptiles, and mammals, while crocodilian, turtle, and avian genomes exhibit reduced microsatellite landscapes. We used comparative methods to infer evolutionary rates of change in microsatellite abundance across vertebrates and to highlight particular lineages that have experienced unusually high or low rates of change in genomic microsatellite abundance. Overall, most variation in microsatellite content, abundance, and evolutionary rate is observed among major lineages of reptiles, yet we found that several deeply divergent clades (i.e., squamate reptiles and mammals) contained relatively similar genomic microsatellite compositions. Archosauromorph reptiles (turtles, crocodilians, and birds) exhibit reduced genomic microsatellite content and the slowest rates of microsatellite evolution, in contrast to squamate reptile genomes that have among the highest rates of microsatellite evolution. Substantial branch-specific shifts in SSR content in primates, monotremes, rodents, snakes, and fish are also evident. Collectively, our results support multiple major shifts in microsatellite genomic landscapes among vertebrates.
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Affiliation(s)
- Richard H Adams
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Heath Blackmon
- b Department of Ecology, Evolution & Behavior, 1987 Upper Buford Cir., University of Minnesota, Saint Paul, MN 55108-6097, USA
| | - Jacobo Reyes-Velasco
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Drew R Schield
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Daren C Card
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Audra L Andrew
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Nyimah Waynewood
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
| | - Todd A Castoe
- a Department of Biology, 501 S. Nedderman Dr., University of Texas at Arlington, TX 76019, USA
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Schield DR, Walsh MR, Card DC, Andrew AL, Adams RH, Castoe TA. Epi
RAD
seq: scalable analysis of genomewide patterns of methylation using next‐generation sequencing. Methods Ecol Evol 2015. [DOI: 10.1111/2041-210x.12435] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Drew R. Schield
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
| | - Matthew R. Walsh
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
| | - Daren C. Card
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
| | - Audra L. Andrew
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
| | - Richard H. Adams
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
| | - Todd A. Castoe
- Department of Biology University of Texas at Arlington 501 S. Nedderman Dr. Arlington TX 76019 USA
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Andrew AL, Card DC, Ruggiero RP, Schield DR, Adams RH, Pollock DD, Secor SM, Castoe TA. Rapid changes in gene expression direct rapid shifts in intestinal form and function in the Burmese python after feeding. Physiol Genomics 2015; 47:147-57. [PMID: 25670730 DOI: 10.1152/physiolgenomics.00131.2014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/05/2015] [Indexed: 12/21/2022] Open
Abstract
Snakes provide a unique and valuable model system for studying the extremes of physiological remodeling because of the ability of some species to rapidly upregulate organ form and function upon feeding. The predominant model species used to study such extreme responses has been the Burmese python because of the extreme nature of postfeeding response in this species. We analyzed the Burmese python intestine across a time series, before, during, and after feeding to understand the patterns and timing of changes in gene expression and their relationship to changes in intestinal form and function upon feeding. Our results indicate that >2,000 genes show significant changes in expression in the small intestine following feeding, including genes involved in intestinal morphology and function (e.g., hydrolases, microvillus proteins, trafficking and transport proteins), as well as genes involved in cell division and apoptosis. Extensive changes in gene expression occur surprisingly rapidly, within the first 6 h of feeding, coincide with changes in intestinal morphology, and effectively return to prefeeding levels within 10 days. Collectively, our results provide an unprecedented portrait of parallel changes in gene expression and intestinal morphology and physiology on a scale that is extreme both in the magnitude of changes, as well as in the incredibly short time frame of these changes, with up- and downregulation of expression and function occurring in the span of 10 days. Our results also identify conserved vertebrate signaling pathways that modulate these responses, which may suggest pathways for therapeutic modulation of intestinal function in humans.
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Affiliation(s)
- Audra L Andrew
- Department of Biology, The University of Texas at Arlington, Arlington, Texas
| | - Daren C Card
- Department of Biology, The University of Texas at Arlington, Arlington, Texas
| | - Robert P Ruggiero
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Drew R Schield
- Department of Biology, The University of Texas at Arlington, Arlington, Texas
| | - Richard H Adams
- Department of Biology, The University of Texas at Arlington, Arlington, Texas
| | - David D Pollock
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Stephen M Secor
- Department of Biological Sciences, University of Alabama, Tuscaloosa, Alabama
| | - Todd A Castoe
- Department of Biology, The University of Texas at Arlington, Arlington, Texas;
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Schield DR, Card DC, Adams RH, Jezkova T, Reyes-Velasco J, Proctor FN, Spencer CL, Herrmann HW, Mackessy SP, Castoe TA. Incipient speciation with biased gene flow between two lineages of the Western Diamondback Rattlesnake (Crotalus atrox). Mol Phylogenet Evol 2014; 83:213-23. [PMID: 25534232 DOI: 10.1016/j.ympev.2014.12.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/03/2014] [Accepted: 12/09/2014] [Indexed: 10/24/2022]
Abstract
We used mitochondrial DNA sequence data from 151 individuals to estimate population genetic structure across the range of the Western Diamondback Rattlesnake (Crotalus atrox), a widely distributed North American pit viper. We also tested hypotheses of population structure using double-digest restriction site associated DNA (ddRADseq) data, incorporating thousands of nuclear genome-wide SNPs from 42 individuals. We found strong mitochondrial support for a deep divergence between eastern and western C. atrox populations, and subsequent intermixing of these populations in the Inter-Pecos region of the United States and Mexico. Our nuclear RADseq data also identify these two distinct lineages of C. atrox, and provide evidence for nuclear admixture of eastern and western alleles across a broad geographic region. We identified contrasting patterns of mitochondrial and nuclear genetic variation across this genetic fusion zone that indicate partially restricted patterns of gene flow, which may be due to either pre- or post-zygotic isolating mechanisms. The failure of these two lineages to maintain complete genetic isolation, and evidence for partially-restricted gene flow, imply that these lineages were in the early stages of speciation prior to secondary contact.
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Affiliation(s)
- Drew R Schield
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Daren C Card
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Richard H Adams
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Tereza Jezkova
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, USA
| | - Jacobo Reyes-Velasco
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - F Nicole Proctor
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Carol L Spencer
- Museum of Vertebrate Zoology, 3101 Valley Life Sciences Building, University of California, Berkeley, CA 94720, USA
| | - Hans-Werner Herrmann
- School of Natural Resources and the Environment, 1041 E Lowell Street, University of Arizona, Tuscon, AZ 85721, USA
| | - Stephen P Mackessy
- School of Biological Sciences, 501 20(th) Street, University of Northern Colorado, Greeley, CO 80639, USA
| | - Todd A Castoe
- Department of Biology & Amphibian and Reptile Diversity Research Center, 501 S. Nedderman Drive, University of Texas at Arlington, Arlington, TX 76019, USA.
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Jezkova T, Riddle BR, Card DC, Schield DR, Eckstut ME, Castoe TA. Genetic consequences of postglacial range expansion in two codistributed rodents (genusDipodomys) depend on ecology and genetic locus. Mol Ecol 2014; 24:83-97. [DOI: 10.1111/mec.13012] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 11/16/2014] [Accepted: 11/19/2014] [Indexed: 01/18/2023]
Affiliation(s)
- Tereza Jezkova
- School of Life Sciences; University of Nevada Las Vegas; 4505 Maryland Parkway Las Vegas NV 89154 USA
| | - Brett R. Riddle
- School of Life Sciences; University of Nevada Las Vegas; 4505 Maryland Parkway Las Vegas NV 89154 USA
| | - Daren C. Card
- Department of Biology; The University of Texas at Arlington; 501 South Nedderman Drive Arlington TX 76010 USA
| | - Drew R. Schield
- Department of Biology; The University of Texas at Arlington; 501 South Nedderman Drive Arlington TX 76010 USA
| | - Mallory E. Eckstut
- School of Life Sciences; University of Nevada Las Vegas; 4505 Maryland Parkway Las Vegas NV 89154 USA
| | - Todd A. Castoe
- Department of Biology; The University of Texas at Arlington; 501 South Nedderman Drive Arlington TX 76010 USA
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Reyes-Velasco J, Card DC, Andrew AL, Shaney KJ, Adams RH, Schield DR, Casewell NR, Mackessy SP, Castoe TA. Expression of venom gene homologs in diverse python tissues suggests a new model for the evolution of snake venom. Mol Biol Evol 2014; 32:173-83. [PMID: 25338510 DOI: 10.1093/molbev/msu294] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Snake venom gene evolution has been studied intensively over the past several decades, yet most previous studies have lacked the context of complete snake genomes and the full context of gene expression across diverse snake tissues. We took a novel approach to studying snake venom evolution by leveraging the complete genome of the Burmese python, including information from tissue-specific patterns of gene expression. We identified the orthologs of snake venom genes in the python genome, and conducted detailed analysis of gene expression of these venom homologs to identify patterns that differ between snake venom gene families and all other genes. We found that venom gene homologs in the python are expressed in many different tissues outside of oral glands, which illustrates the pitfalls of using transcriptomic data alone to define "venom toxins." We hypothesize that the python may represent an ancestral state prior to major venom development, which is supported by our finding that the expansion of venom gene families is largely restricted to highly venomous caenophidian snakes. Therefore, the python provides insight into biases in which genes were recruited for snake venom systems. Python venom homologs are generally expressed at lower levels, have higher variance among tissues, and are expressed in fewer organs compared with all other python genes. We propose a model for the evolution of snake venoms in which venom genes are recruited preferentially from genes with particular expression profile characteristics, which facilitate a nearly neutral transition toward specialized venom system expression.
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Affiliation(s)
| | - Daren C Card
- Department of Biology, University of Texas at Arlington
| | | | - Kyle J Shaney
- Department of Biology, University of Texas at Arlington
| | | | | | - Nicholas R Casewell
- Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Todd A Castoe
- Department of Biology, University of Texas at Arlington
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Card DC, Schield DR, Reyes-Velasco J, Fujita MK, Andrew AL, Oyler-McCance SJ, Fike JA, Tomback DF, Ruggiero RP, Castoe TA. Two low coverage bird genomes and a comparison of reference-guided versus de novo genome assemblies. PLoS One 2014; 9:e106649. [PMID: 25192061 PMCID: PMC4156343 DOI: 10.1371/journal.pone.0106649] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 08/07/2014] [Indexed: 12/04/2022] Open
Abstract
As a greater number and diversity of high-quality vertebrate reference genomes become available, it is increasingly feasible to use these references to guide new draft assemblies for related species. Reference-guided assembly approaches may substantially increase the contiguity and completeness of a new genome using only low levels of genome coverage that might otherwise be insufficient for de novo genome assembly. We used low-coverage (∼3.5-5.5x) Illumina paired-end sequencing to assemble draft genomes of two bird species (the Gunnison Sage-Grouse, Centrocercus minimus, and the Clark's Nutcracker, Nucifraga columbiana). We used these data to estimate de novo genome assemblies and reference-guided assemblies, and compared the information content and completeness of these assemblies by comparing CEGMA gene set representation, repeat element content, simple sequence repeat content, and GC isochore structure among assemblies. Our results demonstrate that even lower-coverage genome sequencing projects are capable of producing informative and useful genomic resources, particularly through the use of reference-guided assemblies.
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Affiliation(s)
- Daren C. Card
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
| | - Drew R. Schield
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
| | - Jacobo Reyes-Velasco
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
| | - Matthew K. Fujita
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
| | - Audra L. Andrew
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
| | - Sara J. Oyler-McCance
- United States Geological Survey – Fort Collins Science Center, Fort Collins, Colorado, United States of America
| | - Jennifer A. Fike
- United States Geological Survey – Fort Collins Science Center, Fort Collins, Colorado, United States of America
| | - Diana F. Tomback
- Department of Integrative Biology, University of Colorado Denver, Denver, Colorado, United States of America
| | - Robert P. Ruggiero
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Todd A. Castoe
- Department of Biology, The University of Texas at Arlington, Arlington, Texas, United States of America
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