1
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Mira-Jover A, Graciá E, Giménez A, Fritz U, Rodríguez-Caro RC, Bourgeois Y. Taking advantage of reference-guided assembly in a slowly-evolving lineage: Application to Testudo graeca. PLoS One 2024; 19:e0303408. [PMID: 39121089 PMCID: PMC11315351 DOI: 10.1371/journal.pone.0303408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 07/22/2024] [Indexed: 08/11/2024] Open
Abstract
BACKGROUND Obtaining de novo chromosome-level genome assemblies greatly enhances conservation and evolutionary biology studies. For many research teams, long-read sequencing technologies (that produce highly contiguous assemblies) remain unaffordable or unpractical. For the groups that display high synteny conservation, these limitations can be overcome by a reference-guided assembly using a close relative genome. Among chelonians, tortoises (Testudinidae) are considered one of the most endangered taxa, which calls for more genomic resources. Here we make the most of high synteny conservation in chelonians to produce the first chromosome-level genome assembly of the genus Testudo with one of the most iconic tortoise species in the Mediterranean basin: Testudo graeca. RESULTS We used high-quality, paired-end Illumina sequences to build a reference-guided assembly with the chromosome-level reference of Gopherus evgoodei. We reconstructed a 2.29 Gb haploid genome with a scaffold N50 of 107.598 Mb and 5.37% gaps. We sequenced 25,998 protein-coding genes, and identified 41.2% of the assembly as repeats. Demographic history reconstruction based on the genome revealed two events (population decline and recovery) that were consistent with previously suggested phylogeographic patterns for the species. This outlines the value of such reference-guided assemblies for phylogeographic studies. CONCLUSIONS Our results highlight the value of using close relatives to produce de novo draft assemblies in species where such resources are unavailable. Our annotated genome of T. graeca paves the way to delve deeper into the species' evolutionary history and provides a valuable resource to enhance direct conservation efforts on their threatened populations.
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Affiliation(s)
- Andrea Mira-Jover
- Ecology Area, University Institute for Agro-food and Agro-environmental Research and Innovation (CIAGRO), Miguel Hernández University, Elche, Carretera de Beniel, Orihuela (Alicante), Spain
| | - Eva Graciá
- Ecology Area, University Institute for Agro-food and Agro-environmental Research and Innovation (CIAGRO), Miguel Hernández University, Elche, Carretera de Beniel, Orihuela (Alicante), Spain
| | - Andrés Giménez
- Ecology Area, University Institute for Agro-food and Agro-environmental Research and Innovation (CIAGRO), Miguel Hernández University, Elche, Carretera de Beniel, Orihuela (Alicante), Spain
| | - Uwe Fritz
- Museum of Zoology, Senckenberg Dresden, Dresden, Germany
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2
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Gable SM, Bushroe NA, Mendez JM, Wilson A, Pinto BJ, Gamble T, Tollis M. Differential Conservation and Loss of Chicken Repeat 1 (CR1) Retrotransposons in Squamates Reveal Lineage-Specific Genome Dynamics Across Reptiles. Genome Biol Evol 2024; 16:evae157. [PMID: 39031594 PMCID: PMC11303007 DOI: 10.1093/gbe/evae157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 07/09/2024] [Accepted: 07/11/2024] [Indexed: 07/22/2024] Open
Abstract
Transposable elements (TEs) are repetitive DNA sequences which create mutations and generate genetic diversity across the tree of life. In amniote vertebrates, TEs have been mainly studied in mammals and birds, whose genomes generally display low TE diversity. Squamates (Order Squamata; including ∼11,000 extant species of lizards and snakes) show as much variation in TE abundance and activity as they do in species and phenotypes. Despite this high TE activity, squamate genomes are remarkably uniform in size. We hypothesize that novel, lineage-specific genome dynamics have evolved over the course of squamate evolution. To understand the interplay between TEs and host genomes, we analyzed the evolutionary history of the chicken repeat 1 (CR1) retrotransposon, a TE family found in most tetrapod genomes which is the dominant TE in most reptiles. We compared 113 squamate genomes to the genomes of turtles, crocodilians, and birds and used ancestral state reconstruction to identify shifts in the rate of CR1 copy number evolution across reptiles. We analyzed the repeat landscapes of CR1 in squamate genomes and determined that shifts in the rate of CR1 copy number evolution are associated with lineage-specific variation in CR1 activity. We then used phylogenetic reconstruction of CR1 subfamilies across amniotes to reveal both recent and ancient CR1 subclades across the squamate tree of life. The patterns of CR1 evolution in squamates contrast other amniotes, suggesting key differences in how TEs interact with different host genomes and at different points across evolutionary history.
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Affiliation(s)
- Simone M Gable
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Nicholas A Bushroe
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Jasmine M Mendez
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Adam Wilson
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Brendan J Pinto
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI, USA
| | - Tony Gamble
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI, USA
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
- Bell Museum of Natural History, University of Minnesota, St. Paul, MN, USA
| | - Marc Tollis
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
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3
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Hassan NT, Galbraith JD, Adelson DL. Multiple horizontal transfer events of a DNA transposon into turtles, fishes, and a frog. Mob DNA 2024; 15:7. [PMID: 38605364 PMCID: PMC11008031 DOI: 10.1186/s13100-024-00318-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 03/19/2024] [Indexed: 04/13/2024] Open
Abstract
Horizontal transfer of transposable elements (HTT) has been reported across many species and the impact of such events on genome structure and function has been well described. However, few studies have focused on reptilian genomes, especially HTT events in Testudines (turtles). Here, as a consequence of investigating the repetitive content of Malaclemys terrapin terrapin (Diamondback turtle) we found a high similarity DNA transposon, annotated in RepBase as hAT-6_XT, shared between other turtle species, ray-finned fishes, and a frog. hAT-6_XT was notably absent in reptilian taxa closely related to turtles, such as crocodiles and birds. Successful invasion of DNA transposons into new genomes requires the conservation of specific residues in the encoded transposase, and through structural analysis, these residues were identified indicating some retention of functional transposition activity. We document six recent independent HTT events of a DNA transposon in turtles, which are known to have a low genomic evolutionary rate and ancient repeats.
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Affiliation(s)
- Nozhat T Hassan
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - James D Galbraith
- Institute of Ecology and Evolution, University of Edinburgh, Edinburgh, UK
| | - David L Adelson
- School of Biological Sciences, University of Adelaide, Adelaide, Australia.
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4
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Gable SM, Bushroe N, Mendez J, Wilson A, Pinto B, Gamble T, Tollis M. Differential Conservation and Loss of CR1 Retrotransposons in Squamates Reveals Lineage-Specific Genome Dynamics across Reptiles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579686. [PMID: 38405926 PMCID: PMC10888918 DOI: 10.1101/2024.02.09.579686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Transposable elements (TEs) are repetitive DNA sequences which create mutations and generate genetic diversity across the tree of life. In amniotic vertebrates, TEs have been mainly studied in mammals and birds, whose genomes generally display low TE diversity. Squamates (Order Squamata; ~11,000 extant species of lizards and snakes) show as much variation in TE abundance and activity as they do in species and phenotypes. Despite this high TE activity, squamate genomes are remarkably uniform in size. We hypothesize that novel, lineage-specific dynamics have evolved over the course of squamate evolution to constrain genome size across the order. Thus, squamates may represent a prime model for investigations into TE diversity and evolution. To understand the interplay between TEs and host genomes, we analyzed the evolutionary history of the CR1 retrotransposon, a TE family found in most tetrapod genomes. We compared 113 squamate genomes to the genomes of turtles, crocodilians, and birds, and used ancestral state reconstruction to identify shifts in the rate of CR1 copy number evolution across reptiles. We analyzed the repeat landscapes of CR1 in squamate genomes and determined that shifts in the rate of CR1 copy number evolution are associated with lineage-specific variation in CR1 activity. We then used phylogenetic reconstruction of CR1 subfamilies across amniotes to reveal both recent and ancient CR1 subclades across the squamate tree of life. The patterns of CR1 evolution in squamates contrast other amniotes, suggesting key differences in how TEs interact with different host genomes and at different points across evolutionary history.
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Affiliation(s)
- Simone M. Gable
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Nicholas Bushroe
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Jasmine Mendez
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Adam Wilson
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
| | - Brendan Pinto
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI, USA
| | - Tony Gamble
- Department of Zoology, Milwaukee Public Museum, Milwaukee, WI, USA
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
- Bell Museum of Natural History, University of Minnesota, St. Paul, MN, USA
| | - Marc Tollis
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ, USA
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5
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Gable SM, Mendez JM, Bushroe NA, Wilson A, Byars MI, Tollis M. The State of Squamate Genomics: Past, Present, and Future of Genome Research in the Most Speciose Terrestrial Vertebrate Order. Genes (Basel) 2023; 14:1387. [PMID: 37510292 PMCID: PMC10379679 DOI: 10.3390/genes14071387] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/30/2023] Open
Abstract
Squamates include more than 11,000 extant species of lizards, snakes, and amphisbaenians, and display a dazzling diversity of phenotypes across their over 200-million-year evolutionary history on Earth. Here, we introduce and define squamates (Order Squamata) and review the history and promise of genomic investigations into the patterns and processes governing squamate evolution, given recent technological advances in DNA sequencing, genome assembly, and evolutionary analysis. We survey the most recently available whole genome assemblies for squamates, including the taxonomic distribution of available squamate genomes, and assess their quality metrics and usefulness for research. We then focus on disagreements in squamate phylogenetic inference, how methods of high-throughput phylogenomics affect these inferences, and demonstrate the promise of whole genomes to settle or sustain persistent phylogenetic arguments for squamates. We review the role transposable elements play in vertebrate evolution, methods of transposable element annotation and analysis, and further demonstrate that through the understanding of the diversity, abundance, and activity of transposable elements in squamate genomes, squamates can be an ideal model for the evolution of genome size and structure in vertebrates. We discuss how squamate genomes can contribute to other areas of biological research such as venom systems, studies of phenotypic evolution, and sex determination. Because they represent more than 30% of the living species of amniote, squamates deserve a genome consortium on par with recent efforts for other amniotes (i.e., mammals and birds) that aim to sequence most of the extant families in a clade.
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Affiliation(s)
- Simone M Gable
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Jasmine M Mendez
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Nicholas A Bushroe
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Adam Wilson
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Michael I Byars
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Marc Tollis
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, Flagstaff, AZ 86011, USA
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6
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Antonio Baeza J, Rajapakse D, Pearson L, Kreiser BR. Low coverage sequencing provides insights into the key features of the nuclear and mitochondrial genomes of the Alligator Snapping Turtle Macrochelys temminckii. Gene 2023; 873:147478. [PMID: 37182558 DOI: 10.1016/j.gene.2023.147478] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 04/24/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Abstract
The alligator snapping turtle Macrochelys temminckii is a culturally, ecologically, and evolutionary relevant species of conservation concern. In this study, we conducted a genome survey of M. temminckii. Using a low-coverage short read sequencing strategy, this study estimated the genome size, repetitive genome content, annotated and quantified repetitive elements, assembled the 45S rRNA DNA operon, and characterized in detail the mitochondrial genome of M. temminckii. Using a k-mer strategy, the estimated haploid genome size varied between 3.77 and 3.19 Gbp, which is within the range previously reported for other representatives of the family Chelydridae. Repetitive genome content estimates using different k-mers (21 to 51) indicated that more than 75% of the genome of M. temminckii comprised repetitive elements. Taking into account only annotated repetitive elements, the most common repetitive elements were classified as Class I - Long Interspersed Nuclear Element (LINE) which were more abundant than Class I - Penelope and Class I - Long Terminal Repeat (LTR) Ty3-gypsy mobile elements. Less abundant repeat element families in the nuclear genome of M. temminckii included Class I - DIRS mobile elements and Satellite DNA. The nuclear ribosomal operon was partially assembled into two contigs, one encoding the complete ssrDNA and a second comprising the full lsrDNA. The AT-rich complete mitochondrial genome was 16,570 bp long. These new genomic resources are of utmost importance to aid in the development of conservation plans for this freshwater turtle.
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Affiliation(s)
- J Antonio Baeza
- Department of Biological Sciences, Clemson University, Clemson, SC, USA; Departamento de Biología Marina, Universidad Catolica del Norte, Coquimbo, Chile; Smithsonian Marine Station at Fort Pierce, Smithsonian Institution, Fort Pierce, FL, USA.
| | - Dilani Rajapakse
- Department of Biological Sciences, Clemson University, Clemson, SC, USA
| | - Luke Pearson
- U.S. Fish and Wildlife Service, Mississippi Ecological Services Field Office, 6578 Dogwood View Parkway, Jackson, MS 39213
| | - Brian R Kreiser
- School of Biological, Environmental and Earth Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406 USA
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7
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Parker LD, Quinta JD, Rivera I, Cypher BL, Kelly EC, Campana MG, Fleischer RC, Boarman R, Boarman WI, Maldonado JE. Genetic analyses are more sensitive than morphological inspection at detecting the presence of threatened Mojave desert tortoise (
Gopherus agassizii
) remains in canid scat and raven pellets. CONSERVATION SCIENCE AND PRACTICE 2022. [DOI: 10.1111/csp2.12689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Lillian D. Parker
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
- School of Systems Biology George Mason University Virginia USA
| | - Jessica D. Quinta
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
| | - Isabel Rivera
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
| | - Brian L. Cypher
- Endangered Species Recovery Program California State University Stanislaus Turlock California USA
| | - Erica C. Kelly
- Endangered Species Recovery Program California State University Stanislaus Turlock California USA
| | - Michael G. Campana
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
- School of Systems Biology George Mason University Virginia USA
- Department of Environmental Science and Policy George Mason University Virginia USA
| | - Robert C. Fleischer
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
| | - Ryan Boarman
- Conservation Science Research and Consultation Spring Valley California USA
| | - William I. Boarman
- Conservation Science Research and Consultation Spring Valley California USA
| | - Jesús E. Maldonado
- Center for Conservation Genomics Smithsonian Conservation Biology Institute and National Zoological Park Washington District of Columbia USA
- School of Systems Biology George Mason University Virginia USA
- Department of Environmental Science and Policy George Mason University Virginia USA
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8
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Gable SM, Byars MI, Literman R, Tollis M. A Genomic Perspective on the Evolutionary Diversification of Turtles. Syst Biol 2022; 71:1331-1347. [DOI: 10.1093/sysbio/syac019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract
To examine phylogenetic heterogeneity in turtle evolution, we collected thousands of high-confidence single-copy orthologs from 19 genome assemblies representative of extant turtle diversity and estimated a phylogeny with multispecies coalescent and concatenated partitioned methods. We also collected next-generation sequences from 26 turtle species and assembled millions of biallelic markers to reconstruct phylogenies based on annotated regions from the western painted turtle (Chrysemys picta bellii) genome (coding regions, introns, untranslated regions, intergenic, and others). We then measured gene tree-species tree discordance, as well as gene and site heterogeneity at each node in the inferred trees, and tested for temporal patterns in phylogenomic conflict across turtle evolution. We found strong and consistent support for all bifurcations in the inferred turtle species phylogenies. However, a number of genes, sites, and genomic features supported alternate relationships between turtle taxa. Our results suggest that gene tree-species tree discordance in these datasets is likely driven by population-level processes such as incomplete lineage sorting. We found very little effect of substitutional saturation on species tree topologies, and no clear phylogenetic patterns in codon usage bias and compositional heterogeneity. There was no correlation between gene and site concordance, node age, and DNA substitution rate across most annotated genomic regions. Our study demonstrates that heterogeneity is to be expected even in well resolved clades such as turtles, and that future phylogenomic studies should aim to sample as much of the genome as possible in order to obtain accurate phylogenies for assessing conservation priorities in turtles.
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Affiliation(s)
- Simone M Gable
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, PO Box 5693, Flagstaff, AZ 8601, USA
| | - Michael I Byars
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, PO Box 5693, Flagstaff, AZ 8601, USA
| | - Robert Literman
- Department of Biological Sciences, University of Rhode Island, 120 Flagg Road, Kingstown, RI, 0288, USA
| | - Marc Tollis
- School of Informatics, Computing, and Cyber Systems, Northern Arizona University, PO Box 5693, Flagstaff, AZ 8601, USA
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9
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Ren Y, Zhang Q, Yan X, Hou D, Huang H, Li C, Rao D, Li Y. Genomic insights into the evolution of the critically endangered soft‐shelled turtle
Rafetus swinhoei. Mol Ecol Resour 2022; 22:1972-1985. [DOI: 10.1111/1755-0998.13596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 01/07/2022] [Accepted: 02/07/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Yandong Ren
- State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China
| | - Qiang Zhang
- Changsha Ecological Zoo Changsha 410002 China
| | - Xiahui Yan
- Changsha Ecological Zoo Changsha 410002 China
| | - Dongmin Hou
- State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China
| | | | - Chunhui Li
- Changsha Ecological Zoo Changsha 410002 China
| | - Dingqi Rao
- State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China
| | - Yongxin Li
- State Key Laboratory of Genetic Resources and Evolution Kunming Institute of Zoology Chinese Academy of Sciences Kunming 650223 China
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10
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Liu J, Liu S, Zheng K, Tang M, Gu L, Young J, Wang Z, Qiu Y, Dong J, Gu S, Xiong L, Zhou R, Nie L. Chromosome-level genome assembly of the Chinese three-keeled pond turtle (Mauremys reevesii) provides insights into freshwater adaptation. Mol Ecol Resour 2021; 22:1596-1605. [PMID: 34845835 DOI: 10.1111/1755-0998.13563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 11/27/2022]
Abstract
Mauremys reevesii is an endangered freshwater turtle that symbolizes longevity in Chinese culture. Despite its importance, genetic studies of this species remain limited, with no genomic sequence reported to date. Here, we report a high-quality, chromosome-level genomic sequence of M. reevesii obtained using a combination of Nanopore and Hi-C sequencing technologies. The 2.37 Gb M. reevesii genome was assembled from a total of ~226.80 Gb of Nanopore sequencing data. The M. reevesii genome contig N50 is 34.73 Mb, the highest value in published turtle genomes. In total, 18,238 genes were functionally annotated. The contigs were clustered and ordered onto 27 pseudochromosomes covering ~96.55% of the genome assembled with Hi-C data. To explore genome evolution, synteny analysis was performed between M. reevesii (freshwater turtle) and Gopherus evgoodei (terrestrial turtle) genomes. In general, each chromosome of M. reevesii corresponded to one chromosome of Gopherus evgoodei, but some interchromosomal rearrangements occurred between the two species based on the assembled genomes. These interchromosomal rearrangements were further confirmed by mapping of the long-read nanopore data to the assembly. The reconstructed demographic history showed varied effective population size among freshwater, marine and terrestrial turtles. We also discovered expansion of genes related to the innate immune system in M. reevesii that may provide defence against freshwater pathogens. The high-quality genomic sequence provides a valuable genetic resource for further studies of genetics and genome evolution in turtles.
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Affiliation(s)
- Jianjun Liu
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China.,Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Siqi Liu
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
| | - Kai Zheng
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
| | - Min Tang
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
| | - Liping Gu
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - James Young
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Ziming Wang
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
| | - Yeyan Qiu
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Jinxiu Dong
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
| | | | | | - Ruanbao Zhou
- Department of Biology and Microbiology, South Dakota State University, Brookings, South Dakota, USA
| | - Liuwang Nie
- Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui, College of Life Science, Anhui Normal University, Wuhu, China
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11
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Álvarez-Varas R, Rojas-Hernández N, Heidemeyer M, Riginos C, Benítez HA, Araya-Donoso R, Reséndiz E, Lara-Uc M, Godoy DA, Muñoz-Pérez JP, Alarcón-Ruales DE, Alfaro-Shigueto J, Ortiz-Alvarez C, Mangel JC, Vianna JA, Véliz D. Green, yellow or black? Genetic differentiation and adaptation signatures in a highly migratory marine turtle. Proc Biol Sci 2021; 288:20210754. [PMID: 34229490 DOI: 10.1098/rspb.2021.0754] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Marine species may exhibit genetic structure accompanied by phenotypic differentiation related to adaptation despite their high mobility. Two shape-based morphotypes have been identified for the green turtle (Chelonia mydas) in the Pacific Ocean: the south-central/western or yellow turtle and north-central/eastern or black turtle. The genetic differentiation between these morphotypes and the adaptation of the black turtle to environmentally contrasting conditions of the eastern Pacific region has remained a mystery for decades. Here we addressed both questions using a reduced-representation genome approach (Dartseq; 9473 neutral SNPs) and identifying candidate outlier loci (67 outlier SNPs) of biological relevance between shape-based morphotypes from eight Pacific foraging grounds (n = 158). Our results support genetic divergence between morphotypes, probably arising from strong natal homing behaviour. Genes and enriched biological functions linked to thermoregulation, hypoxia, melanism, morphogenesis, osmoregulation, diet and reproduction were found to be outliers for differentiation, providing evidence for adaptation of C. mydas to the eastern Pacific region and suggesting independent evolutionary trajectories of the shape-based morphotypes. Our findings support the evolutionary distinctness of the enigmatic black turtle and contribute to the adaptive research and conservation genomics of a long-lived and highly mobile vertebrate.
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Affiliation(s)
- Rocío Álvarez-Varas
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile.,Qarapara Tortugas Marinas Chile NGO, Santiago, Chile
| | - Noemi Rojas-Hernández
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Maike Heidemeyer
- Centro de Investigación en Biología Celular y Molecular (CIBCM), Universidad de Costa Rica, San José, Costa Rica
| | - Cynthia Riginos
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Hugo A Benítez
- Laboratorio de Ecología y Morfometría Evolutiva, Centro de Investigación de Estudios Avanzados del Maule, Universidad Católica del Maule, Talca, Chile
| | | | - Eduardo Reséndiz
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Mexico
| | - Mónica Lara-Uc
- Departamento Académico de Ciencias Marinas y Costeras, Universidad Autónoma de Baja California Sur, Mexico
| | - Daniel A Godoy
- Coastal-Marine Research Group, Institute of Natural and Mathematical Sciences, Massey University, Auckland, New Zealand
| | - Juan Pablo Muñoz-Pérez
- Galapagos Science Center GSC (Universidad San Francisco de Quito USFQ-University of North Carolina at Chapel Hill UNC), Isla San Cristobal, Galápagos, Ecuador.,University of the Sunshine Coast USC, 90 Sippy Downs Dr, Sippy Downs, Queensland 4556, Australia
| | - Daniela E Alarcón-Ruales
- Galapagos Science Center GSC (Universidad San Francisco de Quito USFQ-University of North Carolina at Chapel Hill UNC), Isla San Cristobal, Galápagos, Ecuador
| | - Joanna Alfaro-Shigueto
- ProDelphinus, Lima, Peru.,Facultad de Biología Marina, Universidad Científica del Perú, Lima, Peru
| | | | | | - Juliana A Vianna
- Departamento de Ecosistemas y Medio Ambiente, Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - David Véliz
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile
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12
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Araya-Donoso R, San Juan E, Tamburrino Í, Lamborot M, Veloso C, Véliz D. Integrating genetics, physiology and morphology to study desert adaptation in a lizard species. J Anim Ecol 2021; 91:1148-1162. [PMID: 34048024 DOI: 10.1111/1365-2656.13546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 05/24/2021] [Indexed: 11/28/2022]
Abstract
Integration of multiple approaches is key to understand the evolutionary processes of local adaptation and speciation. Reptiles have successfully colonized desert environments, that is, extreme and arid conditions that constitute a strong selective pressure on organisms. Here, we studied genomic, physiological and morphological variations of the lizard Liolaemus fuscus to detect adaptations to the Atacama Desert. By comparing populations of L. fuscus inhabiting the Atacama Desert with populations from the Mediterranean forests from central Chile, we aimed at characterizing features related to desert adaptation. We combined ddRAD sequencing with physiological (evaporative water loss, metabolic rate and selected temperature) and morphological (linear and geometric morphometrics) measurements. We integrated the genomic and phenotypic data using redundancy analyses. Results showed strong genetic divergence, along with a high number of fixed loci between desert and forest populations. Analyses detected 110 fixed and 30 outlier loci located within genes, from which 43 were in coding regions, and 12 presented non-synonymous mutations. The candidate genes were associated with cellular membrane and development. Desert lizards presented lower evaporative water loss than those from the forest. Morphological data showed that desert lizards had smaller body size, different allometry, larger eyeballs and more dorsoventrally compressed heads. Our results suggest incipient speciation between desert and forest populations. The adaptive signal must be cautiously interpreted since genetic drift could also contribute to the divergence pattern. Nonetheless, we propose water and resource availability, and changes in habitat structure, as the most relevant challenges for desert reptiles. This study provides insights of the mechanisms that allow speciation as well as desert adaptation in reptiles at multiple levels, and highlights the benefit of integrating independent evidence.
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Affiliation(s)
- Raúl Araya-Donoso
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile.,School of Life Sciences, Arizona State University, Tempe, AZ, USA
| | - Esteban San Juan
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Ítalo Tamburrino
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Madeleine Lamborot
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Claudio Veloso
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - David Véliz
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Núcleo Milenio de Ecología y Manejo Sustentable de Islas Oceánicas (ESMOI), Departamento de Biología Marina, Universidad Católica del Norte, Coquimbo, Chile
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13
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Cytogenetic Analysis of the Asian Box Turtles of the Genus Cuora (Testudines, Geoemydidae). Genes (Basel) 2021; 12:genes12020156. [PMID: 33503936 PMCID: PMC7911423 DOI: 10.3390/genes12020156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/18/2021] [Accepted: 01/19/2021] [Indexed: 11/18/2022] Open
Abstract
The Asian box turtle genus Cuora currently comprises 13 species with a wide distribution in Southeast Asia, including China and the islands of Indonesia and Philippines. The populations of these species are rapidly declining due to human pressure, including pollution, habitat loss, and harvesting for food consumption. Notably, the IUCN Red List identifies almost all species of the genus Cuora as Endangered (EN) or Critically Endangered (CR). In this study, we explore the karyotypes of 10 Cuora species with conventional (Giemsa staining, C-banding, karyogram reconstruction) and molecular cytogenetic methods (in situ hybridization with probes for rDNA loci and telomeric repeats). Our study reveals a diploid chromosome number of 2n = 52 chromosomes in all studied species, with karyotypes of similar chromosomal morphology. In all examined species, rDNA loci are detected at a single medium-sized chromosome pair and the telomeric repeats are restricted to the expected terminal position across all chromosomes. In contrast to a previous report, sex chromosomes are neither detected in Cuoragalbinifrons nor in any other species. Therefore, we assume that these turtles have either environmental sex determination or genotypic sex determination with poorly differentiated sex chromosomes. The conservation of genome organization could explain the numerous observed cases of interspecific hybridization both within the genus Cuora and across geoemydid turtles.
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14
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Draft Genome of the Common Snapping Turtle, Chelydra serpentina, a Model for Phenotypic Plasticity in Reptiles. G3-GENES GENOMES GENETICS 2020; 10:4299-4314. [PMID: 32998935 PMCID: PMC7718744 DOI: 10.1534/g3.120.401440] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Turtles are iconic reptiles that inhabit a range of ecosystems from oceans to deserts and climates from the tropics to northern temperate regions. Yet, we have little understanding of the genetic adaptations that allow turtles to survive and reproduce in such diverse environments. Common snapping turtles, Chelydra serpentina, are an ideal model species for studying adaptation to climate because they are widely distributed from tropical to northern temperate zones in North America. They are also easy to maintain and breed in captivity and produce large clutch sizes, which makes them amenable to quantitative genetic and molecular genetic studies of traits like temperature-dependent sex determination. We therefore established a captive breeding colony and sequenced DNA from one female using both short and long reads. After trimming and filtering, we had 209.51Gb of Illumina reads, 25.72Gb of PacBio reads, and 21.72 Gb of Nanopore reads. The assembled genome was 2.258 Gb in size and had 13,224 scaffolds with an N50 of 5.59Mb. The longest scaffold was 27.24Mb. BUSCO analysis revealed 97.4% of core vertebrate genes in the genome. We identified 3.27 million SNPs in the reference turtle, which indicates a relatively high level of individual heterozygosity. We assembled the transcriptome using RNA-Seq data and used gene prediction software to produce 22,812 models of protein coding genes. The quality and contiguity of the snapping turtle genome is similar to or better than most published reptile genomes. The genome and genetic variants identified here provide a foundation for future studies of adaptation to climate.
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15
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Scott PA, Allison LJ, Field KJ, Averill-Murray RC, Shaffer HB. Individual heterozygosity predicts translocation success in threatened desert tortoises. Science 2020; 370:1086-1089. [DOI: 10.1126/science.abb0421] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 09/11/2020] [Accepted: 10/20/2020] [Indexed: 12/23/2022]
Affiliation(s)
- Peter A. Scott
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
- Department of Life, Earth, and Environmental Sciences, West Texas A&M University, Canyon, TX 79016, USA
| | - Linda J. Allison
- U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, Reno, NV 89502, USA
| | - Kimberleigh J. Field
- U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, Reno, NV 89502, USA
| | - Roy C. Averill-Murray
- U.S. Fish and Wildlife Service, Desert Tortoise Recovery Office, Reno, NV 89502, USA
| | - H. Bradley Shaffer
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
- La Kretz Center for California Conservation Science, Institute of the Environment and Sustainability, University of California, Los Angeles, CA 90095, USA
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16
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Xu C, Dolby GA, Drake KK, Esque TC, Kusumi K. Immune and sex-biased gene expression in the threatened Mojave desert tortoise, Gopherus agassizii. PLoS One 2020; 15:e0238202. [PMID: 32846428 PMCID: PMC7449761 DOI: 10.1371/journal.pone.0238202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/11/2020] [Indexed: 11/18/2022] Open
Abstract
The immune system of ectotherms, particularly non-avian reptiles, remains poorly characterized regarding the genes involved in immune function, and their function in wild populations. We used RNA-Seq to explore the systemic response of Mojave desert tortoise (Gopherus agassizii) gene expression to three levels of Mycoplasma infection to better understand the host response to this bacterial pathogen. We found over an order of magnitude more genes differentially expressed between male and female tortoises (1,037 genes) than differentially expressed among immune groups (40 genes). There were 8 genes differentially expressed among both variables that can be considered sex-biased immune genes in this tortoise. Among experimental immune groups we find enriched GO biological processes for cysteine catabolism, regulation of type 1 interferon production, and regulation of cytokine production involved in immune response. Sex-biased transcription involves iron ion transport, iron ion homeostasis, and regulation of interferon-beta production to be enriched. More detailed work is needed to assess the seasonal response of the candidate genes found here. How seasonal fluctuation of testosterone and corticosterone modulate the immunosuppression of males and their susceptibility to Mycoplasma infection also warrants further investigation, as well as the importance of iron in the immune function and sex-biased differences of this species. Finally, future transcriptional studies should avoid drawing blood from tortoises via subcarapacial venipuncture as the variable aspiration of lymphatic fluid will confound the differential expression of genes.
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Affiliation(s)
- Cindy Xu
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Greer A. Dolby
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
- Center for Mechanisms of Evolution, Biodesign Institute, Arizona State University, Tempe, Arizona, United States of America
| | - K. Kristina Drake
- Western Ecological Research Center, U.S. Geological Survey, Henderson, Nevada, United States of America
| | - Todd C. Esque
- Western Ecological Research Center, U.S. Geological Survey, Henderson, Nevada, United States of America
| | - Kenro Kusumi
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
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17
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Karyotypic Evolution of Sauropsid Vertebrates Illuminated by Optical and Physical Mapping of the Painted Turtle and Slider Turtle Genomes. Genes (Basel) 2020; 11:genes11080928. [PMID: 32806747 PMCID: PMC7464131 DOI: 10.3390/genes11080928] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/25/2020] [Accepted: 07/31/2020] [Indexed: 02/07/2023] Open
Abstract
Recent sequencing and software enhancements have advanced our understanding of the evolution of genomic structure and function, especially addressing novel evolutionary biology questions. Yet fragmentary turtle genome assemblies remain a challenge to fully decipher the genetic architecture of adaptive evolution. Here, we use optical mapping to improve the contiguity of the painted turtle (Chrysemys picta) genome assembly and use de novo fluorescent in situ hybridization (FISH) of bacterial artificial chromosome (BAC) clones, BAC-FISH, to physically map the genomes of the painted and slider turtles (Trachemys scripta elegans). Optical mapping increased C. picta's N50 by ~242% compared to the previous assembly. Physical mapping permitted anchoring ~45% of the genome assembly, spanning 5544 genes (including 20 genes related to the sex determination network of turtles and vertebrates). BAC-FISH data revealed assembly errors in C. picta and T. s. elegans assemblies, highlighting the importance of molecular cytogenetic data to complement bioinformatic approaches. We also compared C. picta's anchored scaffolds to the genomes of other chelonians, chicken, lizards, and snake. Results revealed a mostly one-to-one correspondence between chromosomes of painted and slider turtles, and high homology among large syntenic blocks shared with other turtles and sauropsids. Yet, numerous chromosomal rearrangements were also evident across chelonians, between turtles and squamates, and between avian and non-avian reptiles.
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18
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Ahmad SF, Singchat W, Jehangir M, Panthum T, Srikulnath K. Consequence of Paradigm Shift with Repeat Landscapes in Reptiles: Powerful Facilitators of Chromosomal Rearrangements for Diversity and Evolution. Genes (Basel) 2020; 11:E827. [PMID: 32708239 PMCID: PMC7397244 DOI: 10.3390/genes11070827] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 12/24/2022] Open
Abstract
Reptiles are notable for the extensive genomic diversity and species richness among amniote classes, but there is nevertheless a need for detailed genome-scale studies. Although the monophyletic amniotes have recently been a focus of attention through an increasing number of genome sequencing projects, the abundant repetitive portion of the genome, termed the "repeatome", remains poorly understood across different lineages. Consisting predominantly of transposable elements or mobile and satellite sequences, these repeat elements are considered crucial in causing chromosomal rearrangements that lead to genomic diversity and evolution. Here, we propose major repeat landscapes in representative reptilian species, highlighting their evolutionary dynamics and role in mediating chromosomal rearrangements. Distinct karyotype variability, which is typically a conspicuous feature of reptile genomes, is discussed, with a particular focus on rearrangements correlated with evolutionary reorganization of micro- and macrochromosomes and sex chromosomes. The exceptional karyotype variation and extreme genomic diversity of reptiles are used to test several hypotheses concerning genomic structure, function, and evolution.
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Affiliation(s)
- Syed Farhan Ahmad
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Worapong Singchat
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Maryam Jehangir
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Integrative Genomics Lab-LGI, Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, São Paulo State University (UNESP), Botucatu 18618-689, Brazil
| | - Thitipong Panthum
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
| | - Kornsorn Srikulnath
- Laboratory of Animal Cytogenetics and Comparative Genomics (ACCG), Department of Genetics, Faculty of Science, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand; (S.F.A.); (W.S.); (M.J.); (T.P.)
- Special Research Unit for Wildlife Genomics (SRUWG), Department of Forest Biology, Faculty of Forestry, Kasetsart University, 50 Ngamwongwan, Chatuchak, Bangkok 10900, Thailand
- Center for Advanced Studies in Tropical Natural Resources, National Research University-Kasetsart University, Kasetsart University, Bangkok 10900, Thailand
- Center of Excellence on Agricultural Biotechnology (AG-BIO/PERDO-CHE), Bangkok 10900, Thailand
- Omics Center for Agriculture, Bioresources, Food and Health, Kasetsart University (OmiKU), Bangkok 10900, Thailand
- Amphibian Research Center, Hiroshima University, 1-3-1, Kagamiyama, Higashihiroshima 739-8526, Japan
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19
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Maldonado JA, Firneno TJ, Roelke CE, Rains ND, Mwgiri J, Fujita MK. Transcriptome sequencing reveals signatures of positive selection in the Spot-Tailed Earless Lizard. PLoS One 2020; 15:e0234504. [PMID: 32542006 PMCID: PMC7295237 DOI: 10.1371/journal.pone.0234504] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 05/26/2020] [Indexed: 11/21/2022] Open
Abstract
The continual loss of threatened biodiversity is occurring at an accelerated pace. High-throughput sequencing technologies are now providing opportunities to address this issue by aiding in the generation of molecular data for many understudied species of high conservation interest. Our overall goal of this study was to begin building the genomic resources to continue investigations and conservation of the Spot-Tailed Earless lizard. Here we leverage the power of high-throughput sequencing to generate the liver transcriptome for the Northern Spot-Tailed Earless Lizard (Holbrookia lacerata) and Southern Spot-Tailed Earless Lizard (Holbrookia subcaudalis), which have declined in abundance in the past decades, and their sister species, the Common Lesser Earless Lizard (Holbrookia maculata). Our efforts produced high quality and robust transcriptome assemblies validated by 1) quantifying the number of processed reads represented in the transcriptome assembly and 2) quantifying the number of highly conserved single-copy orthologs that are present in our transcript set using the BUSCO pipeline. We found 1,361 1-to-1 orthologs among the three Holbrookia species, Anolis carolinensis, and Sceloporus undulatus. We carried out dN/dS selection tests using a branch-sites model and identified a dozen genes that experienced positive selection in the Holbrookia lineage with functions in development, immunity, and metabolism. Our single-copy orthologous sequences additionally revealed significant pairwise sequence divergence (~.73%) between the Northern H. lacerata and Southern H. subcaudalis that further supports the recent elevation of the Southern Spot-Tailed Earless Lizard to full species.
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Affiliation(s)
- Jose A. Maldonado
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, United States of America
| | - Thomas J. Firneno
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, United States of America
| | - Corey E. Roelke
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, United States of America
| | - Nathan D. Rains
- Texas Parks and Wildlife Department, Austin, Texas, TX, United States of America
| | - Juliet Mwgiri
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, United States of America
| | - Matthew K. Fujita
- Department of Biology, Amphibian and Reptile Diversity Research Center, The University of Texas at Arlington, Arlington, TX, United States of America
- * E-mail:
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20
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Dolby GA, Morales M, Webster TH, DeNardo DF, Wilson MA, Kusumi K. Discovery of a New TLR Gene and Gene Expansion Event through Improved Desert Tortoise Genome Assembly with Chromosome-Scale Scaffolds. Genome Biol Evol 2020; 12:3917-3925. [PMID: 32011707 PMCID: PMC7058155 DOI: 10.1093/gbe/evaa016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/20/2020] [Indexed: 12/11/2022] Open
Abstract
Toll-like receptors (TLRs) are a complex family of innate immune genes that are well characterized in mammals and birds but less well understood in nonavian sauropsids (reptiles). The advent of highly contiguous draft genomes of nonmodel organisms enables study of such gene families through analysis of synteny and sequence identity. Here, we analyze TLR genes from the genomes of 22 tetrapod species. Findings reveal a TLR8 gene expansion in crocodilians and turtles (TLR8B), and a second duplication (TLR8C) specifically within turtles, followed by pseudogenization of that gene in the nonfreshwater species (desert tortoise and green sea turtle). Additionally, the Mojave desert tortoise (Gopherus agassizii) has a stop codon in TLR8B (TLR8-1) that is polymorphic among conspecifics. Revised orthology further reveals a new TLR homolog, TLR21-like, which is exclusive to lizards, snakes, turtles, and crocodilians. These analyses were made possible by a new draft genome assembly of the desert tortoise (gopAga2.0), which used chromatin-based assembly to yield draft chromosomal scaffolds (L50 = 26 scaffolds, N50 = 28.36 Mb, longest scaffold = 107 Mb) and an enhanced de novo genome annotation with 25,469 genes. Our three-step approach to orthology curation and comparative analysis of TLR genes shows what new insights are possible using genome assemblies with chromosome-scale scaffolds that permit integration of synteny conservation data.
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Affiliation(s)
- Greer A Dolby
- School of Life Sciences, Arizona State University
- Center for Mechanisms of Evolution, Arizona State University
| | | | - Timothy H Webster
- School of Life Sciences, Arizona State University
- Department of Anthropology, University of Utah
| | | | - Melissa A Wilson
- School of Life Sciences, Arizona State University
- Center for Evolution and Medicine, Arizona State University
| | - Kenro Kusumi
- School of Life Sciences, Arizona State University
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21
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Zhao Z, Heideman N, Grobler P, Jordaan A, Bester P, Hofmeyr MD. Unraveling the diversification and systematic puzzle of the highly polymorphic Psammobates tentorius(Bell, 1828) complex (Reptilia: Testudinidae) through phylogenetic analyses and species delimitation approaches. J ZOOL SYST EVOL RES 2019. [DOI: 10.1111/jzs.12338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Zhongning Zhao
- Department of Zoology and Entomology University of the Free State Bloemfontein South Africa
| | - Neil Heideman
- Department of Zoology and Entomology University of the Free State Bloemfontein South Africa
| | - Paul Grobler
- Department of Genetics University of the Free State Bloemfontein South Africa
| | - Adriaan Jordaan
- Department of Zoology and Entomology University of the Free State Bloemfontein South Africa
| | - Phillip Bester
- Department of Virology University of the Free State and National Health Laboratory Service (NHLS) Bloemfontein South Africa
| | - Margaretha D. Hofmeyr
- Chelonian Biodiversity and Conservation Department of Biodiversity and Conservation Biology University of the Western Cape Bellville South Africa
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22
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Xia T, Zhang H, Zhang L, Yang X, Sun G, Chen J, Xu D, Zhao C. Comparative and evolutionary analysis of the reptilian hedgehog gene family ( Shh, Dhh, and Ihh). PeerJ 2019; 7:e7613. [PMID: 31531274 PMCID: PMC6718155 DOI: 10.7717/peerj.7613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 08/05/2019] [Indexed: 12/25/2022] Open
Abstract
The hedgehog signaling pathway plays a vital role in human and animal patterning and cell proliferation during the developmental process. The hedgehog gene family of vertebrate species includes three genes, Shh, Dhh, and Ihh, which possess different functions and expression patterns. Despite the importance of hedgehog genes, genomic evidence of this gene family in reptiles is lacking. In this study, the available genomes of a number of representative reptile species were explored by utilizing adaptive evolutionary analysis methods to characterize the evolutionary patterns of the hedgehog gene family. Altogether, 33 sonic hedgehog (Shh), 25 desert hedgehog (Dhh), and 20 Indian hedgehog (Ihh) genes were obtained from reptiles, and six avian and five mammalian sequences were added to the analysis. The phylogenetic maximum likelihood (ML) tree of the Shh, Dhh, and Ihh genes revealed a similar topology, which is approximately consistent with the traditional taxonomic group. No shared positive selection site was identified by the PAML site model or the three methods in the Data Monkey Server. Branch model and Clade model C analyses revealed that the Dhh and Ihh genes experienced different evolutionary forces in reptiles and other vertebrates, while the Shh gene was not significantly different in terms of selection pressure. The different evolutionary rates of the Dhh and Ihh genes suggest that these genes may be potential contributors to the discrepant sperm and body development of different clades. The different adaptive evolutionary history of the Shh, Dhh, and Ihh genes among reptiles may be due to their different functions in regulating cellular events of development from the embryonic stages to adulthood. Overall, this study has provided meaningful information regarding the evolution of the hedgehog gene family in reptiles and a theoretical foundation for further analyses on the functional and molecular mechanisms that have shaped the reptilian hedgehog genes.
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Affiliation(s)
- Tian Xia
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Honghai Zhang
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Lei Zhang
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Xiufeng Yang
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Guolei Sun
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Jun Chen
- College of Marine Life Science, Ocean University of Qingdao, Qingdao, Shandong, China
| | - Dajie Xu
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
| | - Chao Zhao
- College of Life Science, Qufu Normal University, Qufu, Shandong, China
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23
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Brejcha J, Bataller JV, Bosáková Z, Geryk J, Havlíková M, Kleisner K, Maršík P, Font E. Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190319. [PMID: 31417734 PMCID: PMC6689573 DOI: 10.1098/rsos.190319] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/28/2019] [Indexed: 05/11/2023]
Abstract
Animal body coloration is a complex trait resulting from the interplay of multiple mechanisms. While many studies address the functions of animal coloration, the mechanisms of colour production still remain unknown in most taxa. Here we compare reflectance spectra, cellular, ultra- and nano-structure of colour-producing elements, and pigment types in two freshwater turtles with contrasting courtship behaviour, Trachemys scripta and Pseudemys concinna. The two species differ in the distribution of pigment cell-types and in pigment diversity. We found xanthophores, melanocytes, abundant iridophores and dermal collagen fibres in stripes of both species. The yellow chin and forelimb stripes of both P. concinna and T. scripta contain xanthophores and iridophores, but the post-orbital regions of the two species differ in cell-type distribution. The yellow post-orbital region of P. concinna contains both xanthophores and iridophores, while T. scripta has only xanthophores in the yellow-red postorbital/zygomatic regions. Moreover, in both species, the xanthophores colouring the yellow-red skin contain carotenoids, pterins and riboflavin, but T. scripta has a higher diversity of pigments than P. concinna. Trachemys s. elegans is sexually dichromatic. Differences in the distribution of pigment cell types across body regions in the two species may be related to visual signalling but do not match predictions based on courtship position. Our results demonstrate that archelosaurs share some colour production mechanisms with amphibians and lepidosaurs (i.e. vertical layering/stacking of different pigment cell types and interplay of carotenoids and pterins), but also employ novel mechanisms (i.e. nano-organization of dermal collagen) shared with mammals.
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Affiliation(s)
- Jindřich Brejcha
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
- Department of Zoology, Natural History Museum, National Museum, Václavské nám. 68, Prague 1, 110 00, Czech Republic
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, Prague 8, 18223, Czech Republic
| | - José Vicente Bataller
- Centro de Conservación de Especies Dulceacuícolas de la Comunidad Valenciana. VAERSA-Generalitat Valenciana, El Palmar, València, 46012, Spain
| | - Zuzana Bosáková
- Department of Analytical Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2, 128 43, Czech Republic
| | - Jan Geryk
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Úvalu 84, 150 06 Prague, Czech Republic
| | - Martina Havlíková
- Department of Analytical Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2, 128 43, Czech Republic
| | - Karel Kleisner
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
| | - Petr Maršík
- Department of Food Science, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6, 165 00, Czech Republic
| | - Enrique Font
- Ethology Lab, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/ Catedrátic José Beltrán Martinez 2, Paterna, València, 46980, Spain
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Affiliation(s)
- J. Whitfield Gibbons
- University of Georgia, Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
| | - Jeffrey E. Lovich
- US Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive MS-9394, Flagstaff, AZ 86001-1600, USA
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25
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Drake KK, Aiello CM, Bowen L, Lewison RL, Esque TC, Nussear KE, Waters SC, Hudson PJ. Complex immune responses and molecular reactions to pathogens and disease in a desert reptile ( Gopherus agassizii). Ecol Evol 2019; 9:2516-2534. [PMID: 30891197 PMCID: PMC6405529 DOI: 10.1002/ece3.4897] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/12/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022] Open
Abstract
Immune function plays an important role in an animal's defense against infectious disease. In reptiles, immune responses may be complex and counterintuitive, and diagnostic tools used to identify infection, such as induced antibody responses are limited. Recent studies using gene transcription profiling in tortoises have proven useful in identifying immune responses to various intrinsic and extrinsic stressors. As part of a larger experiment with Mojave desert tortoises (Gopherus agassizii), we facilitated the transmission of the pathogenic bacteria, Mycoplasma agassizii (Myag), to naïve adults and measured innate and induced immune reactions over time. Specifically, we evaluated clinical condition, presence of Myag in the nasal/oral cavity, induced antibody responses specific to Myag, and measured molecular reactions (gene transcript profiles) in 15 captive tortoises classified as naïve, exposed, or infected and 14 wild tortoises for comparison. Myag was confirmed inside the nasal/oral cavity in exposed tortoises within 30-60 days of introduction to infected animals, yet we did not detect Myag specific induced antibody responses in these individuals until 420-595 days post exposure. Surprisingly, we found no overall differences in the gene transcript profiles between our experimental treatment groups throughout this study. This work highlights the complexities in assessing immune function and diagnosing pathogen related infections in tortoises and other reptiles.
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Affiliation(s)
- K. Kristina Drake
- Western Ecological Research CenterU.S. Geological SurveyHendersonNevada
- Department of BiologySan Diego State UniversitySan DiegoCalifornia
- Graduate Group in EcologyUniversity of California‐DavisDavisCalifornia
| | - Christina M. Aiello
- Western Ecological Research CenterU.S. Geological SurveyHendersonNevada
- Department of BiologyPennsylvania State UniversityUniversity ParkPennsylvania
| | - Lizabeth Bowen
- Western Ecological Research CenterU.S. Geological SurveyDavisCalifornia
| | | | - Todd C. Esque
- Western Ecological Research CenterU.S. Geological SurveyHendersonNevada
| | | | - Shannon C. Waters
- Western Ecological Research CenterU.S. Geological SurveyDavisCalifornia
| | - Peter J. Hudson
- Department of BiologyPennsylvania State UniversityUniversity ParkPennsylvania
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Sánchez-Ramírez S, Rico Y, Berry KH, Edwards T, Karl AE, Henen BT, Murphy RW. Landscape limits gene flow and drives population structure in Agassiz's desert tortoise (Gopherus agassizii). Sci Rep 2018; 8:11231. [PMID: 30046050 PMCID: PMC6060138 DOI: 10.1038/s41598-018-29395-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/09/2018] [Indexed: 12/17/2022] Open
Abstract
Distance, environmental heterogeneity and local adaptation can strongly influence population structure and connectivity. Understanding how these factors shape the genomic landscape of threatened species is a major goal in conservation genomics and wildlife management. Herein, we use thousands (6,859) of single nucleotide polymorphism markers and spatial data from hundreds of individuals (n = 646) to re-evaluate the population structure of Agassiz's desert tortoise (Gopherus agassizii). Analyses resolve from 4 to 8 spatially well-defined clusters across the range. Western, central, and southern populations within the Western Mojave recovery unit are consistent throughout, while analyses sometimes merge other recovery units depending on the level of clustering. Causal modeling consistently associates genetic connectivity with least-cost distance, based on multiple landscape features associated with tortoise habitat, better than geographic distance. Some features include elevation, soil depth, rock volume, precipitation, and vegetation coverage, suggesting that physical, climatic, and biotic landscape features have played a strong evolutionary role restricting gene flow between populations. Further, 12 highly differentiated outlier loci have associated functions that may be involved with neurogenesis, wound healing, lipid metabolism, and possibly vitellogenesis. Together, these findings have important implications for recovery programs, such as translocations, population augmentation, reproduction in captivity and the identification of ecologically important genes, opening new venues for conservation genomics in desert tortoises.
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Affiliation(s)
- Santiago Sánchez-Ramírez
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, M5S 3B2, Toronto, ON, Canada.
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, M5S 2C6, Toronto, ON, Canada.
| | - Yessica Rico
- CONACYT, Red de Diversidad Biológica del Occidente Mexicano, Instituto de Ecología, A. C., Av. Lázaro Cárdenas, 61600, Pátzcuaro, Michoácan, Mexico
| | - Kristin H Berry
- U.S. Geological Survey, Western Ecological Research Center, 21803 Cactus Avenue, Suite F, Riverside, CA, 92518, USA
| | - Taylor Edwards
- University of Arizona Genetics Core, Thomas W. Keating, Bioresearch Building, 1657 E. Helen Street, Room 111, Tucson, AZ, 85721, USA
| | - Alice E Karl
- Alice E. Karl & Associates, 19476 County Road 89, Winters, CA, 9569, USA
| | - Brian T Henen
- Environmental Affairs, MAGTFTC MCAGCC, Twentynine Palms, CA, 92278, USA
| | - Robert W Murphy
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, M5S 3B2, Toronto, ON, Canada.
- Department of Natural History, Royal Ontario Museum, 100 Queen's Park, M5S 2C6, Toronto, ON, Canada.
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Radhakrishnan S, Valenzuela N. Chromosomal Context Affects the Molecular Evolution of Sex-linked Genes and Their Autosomal Counterparts in Turtles and Other Vertebrates. J Hered 2018; 108:720-730. [PMID: 29036698 DOI: 10.1093/jhered/esx082] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/20/2017] [Indexed: 12/11/2022] Open
Abstract
Sex chromosomes evolve differently from autosomes because natural selection acts distinctly on them given their reduced recombination and smaller population size. Various studies of sex-linked genes compared with different autosomal genes within species support these predictions. Here, we take a novel alternative approach by comparing the rate of evolution between subsets of genes that are sex-linked in selected reptiles/vertebrates and the same genes located in autosomes in other amniotes. We report for the first time the faster evolution of Z-linked genes in a turtle (the Chinese softshell turtle Pelodiscus sinensis) relative to autosomal orthologs in other taxa, including turtles with temperature-dependent sex determination (TSD). This faster rate was absent in its close relative, the spiny softshell turtle (Apalone spinifera), thus revealing important lineage effects, and was only surpassed by mammalian-X linked genes. In contrast, we found slower evolution of X-linked genes in the musk turtle Staurotypus triporcatus (XX/XY) and homologous Z-linked chicken genes. TSD lineages displayed overall faster sequence evolution than taxa with genotypic sex determination (GSD), ruling out global effects of GSD on molecular evolution beyond those by sex-linkage. Notably, results revealed a putative selective sweep around two turtle genes involved in vertebrate gonadogenesis (Pelodiscus-Z-linked Nf2 and Chrysemys-autosomal Tspan7). Our observations reveal important evolutionary changes at the gene level mediated by chromosomal context in turtles despite their low overall evolutionary rate and illuminate sex chromosome evolution by empirically testing expectations from theoretical models. Genome-wide analyses are warranted to test the generality and prevalence of the observed patterns.
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Affiliation(s)
- Srihari Radhakrishnan
- Bioinformatics and Computational Biology Program, Iowa State University, Ames, IA 50011
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011
| | - Nicole Valenzuela
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA 50011
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