1
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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] [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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2
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Blais BR, Smith BE, Placyk JS, Casper GS, Spellman GM. Phylogeography of the smooth greensnake, Opheodrys vernalis (Squamata: Colubridae): divergent lineages and variable demographics in a widely distributed yet enigmatic species. Biol J Linn Soc Lond 2021. [DOI: 10.1093/biolinnean/blab124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Abstract
Phylogeographic studies can uncover robust details about the population structure, demographics, and diversity of species. The smooth greensnake, Opheodrys vernalis, is a small, cryptic snake occupying mesic grassland and sparsely wooded habitats. Although O. vernalis has a wide geographical range, many metapopulations are patchy and some are declining. We used mitochondrial DNA and double digest restriction-site associated DNA sequencing to construct the first phylogeographic assessment of O. vernalis. Genomic analysis of 119 individuals (mitochondrial DNA) and a subset of another 45 smooth greensnakes (nuclear DNA; N = 3031 single nucleotide polymorphisms) strongly supports two longitudinally separated lineages, with admixture in the Great Lakes region. Post-Pleistocene secondary contact best explains admixture from populations advancing northwards. Overall, populations expressed low heterozygosity, variable inbreeding rates, and moderate to high differentiation. Disjunct populations in the Rocky Mountains and central Great Plains regions might be contracting relicts, whereas northerly populations in more continuous mesic habitats (e.g., Prairie Pothole region, southern Canada) had signals of population expansion. Broadly, conservation management efforts should be focused on local populations, because habitat connectivity may facilitate gene flow and genetic diversity.
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Affiliation(s)
- Brian R Blais
- School of Natural Sciences, Black Hills State University, Spearfish, SD, USA
| | - Brian E Smith
- School of Natural Sciences, Black Hills State University, Spearfish, SD, USA
| | - John S Placyk
- Department of Biology, University of Texas at Tyler, 3900 University Boulevard, Tyler, TX, USA
| | - Gary S Casper
- University of Wisconsin-Milwaukee Field Station, Saukville, WI, USA
| | - Garth M Spellman
- Department of Zoology, Denver Museum of Nature & Science, 2001 Colorado Boulevard, Denver, CO, USA
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3
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Myers EA. Genome-wide data reveal extensive gene flow during the diversification of the western rattlesnakes (Viperidae: Crotalinae: Crotalus). Mol Phylogenet Evol 2021; 165:107313. [PMID: 34537323 DOI: 10.1016/j.ympev.2021.107313] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 08/28/2021] [Accepted: 09/14/2021] [Indexed: 11/15/2022]
Abstract
Hybridization and introgression are important, but often overlooked processes when inferring phylogenies. When these processes are not accounted for and a strictly diverging phylogenetic model is applied to groups with a history of hybridization, phylogenetic inference and parameter estimation can be inaccurate. Recent developments in phylogenetic network approaches coupled with the increasing availability of genomic data allow inferences of reticulate evolutionary histories across the tree of life. The western rattlesnake species group (C. viridis species complex, C. mitchellii species complex, C. scutulutas, and C. tigris) is an iconic snake lineage that is widespread across western North America. This group is composed of several species complexes with unclear species limits, likely the result of ongoing gene flow among nascent lineages. Here I generate reduced representation genomic data and test for a history of reticulation within this group. I demonstrate that all species have undergone hybridization with at least one other lineage, suggesting introgression is widespread in this group. Topologies differ between phylogenies estimated under the multispecies coalescent and multispecies network coalescent methods, indicating that gene flow has obscured phylogenetic relationships within this group. These past introgression events are predominantly restricted to species that co-occur geographically. However, within species that have a history of introgression, this signature is detected regardless of specimen sampling across geography. Overall, my results suggest the accumulation of reproductive isolating barriers occurs slowly in rattlesnakes which likely leads to the difficulty in delimiting species, furthermore, the results of this study have implications for trait evolution in this group.
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Affiliation(s)
- Edward A Myers
- Department of Herpetology, American Museum of Natural History, New York, NY, USA; Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA.
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4
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Franco-Servín C, Neri-Castro E, Bénard-Valle M, Alagón A, Rosales-García RA, Guerrero-Alba R, Poblano-Sánchez JE, Silva-Briano M, Guerrero-Barrera AL, Sigala-Rodríguez JJ. Biological and Biochemical Characterization of Coronado Island Rattlesnake ( Crotalus helleri caliginis) Venom and Antivenom Neutralization. Toxins (Basel) 2021; 13:toxins13080582. [PMID: 34437453 PMCID: PMC8402616 DOI: 10.3390/toxins13080582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 01/18/2023] Open
Abstract
The Baja California Peninsula has over 250 islands and islets with many endemic species. Among them, rattlesnakes are the most numerous but also one of the least studied groups. The study of island rattlesnake venom could guide us to a better understanding of evolutionary processes and the description of novel toxins. Crotalus helleri caliginis venom samples were analyzed to determine possible ontogenetic variation with SDS-PAGE in one and two dimensions and with RP-HPLC. Western Blot, ELISA, and amino-terminal sequencing were used to determine the main components of the venom. The biological and biochemical activities demonstrate the similarity of C. helleri caliginis venom to the continental species C. helleri helleri, with both having low proteolytic and phospholipase A2 (PLA2) activity but differing due to the absence of neurotoxin (crotoxin-like) in the insular species. The main components of the snake venom were metalloproteases, serine proteases, and crotamine, which was the most abundant toxin group (30–35% of full venom). The crotamine was isolated using size-exclusion chromatography where its functional effects were tested on mouse phrenic nerve–hemidiaphragm preparations in which a significant reduction in muscle twitch contractions were observed. The two Mexican antivenoms could neutralize the lethality of C. helleri caliginis venom but not the crotamine effects.
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Affiliation(s)
- Cristian Franco-Servín
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
- Colección Zoológica, Departamento de Biología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
| | - Edgar Neri-Castro
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001 Colonia Chamilpa, Cuernavaca CP 62210, Morelos, Mexico; (E.N.-C.); (M.B.-V.); (A.A.)
| | - Melisa Bénard-Valle
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001 Colonia Chamilpa, Cuernavaca CP 62210, Morelos, Mexico; (E.N.-C.); (M.B.-V.); (A.A.)
| | - Alejandro Alagón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad # 2001 Colonia Chamilpa, Cuernavaca CP 62210, Morelos, Mexico; (E.N.-C.); (M.B.-V.); (A.A.)
| | - Ramsés Alejandro Rosales-García
- Colección Zoológica, Departamento de Biología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
| | - Raquel Guerrero-Alba
- Laboratorio de Electrofisiología, Departamento de Fisiología y Farmacología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
| | - José Emanuel Poblano-Sánchez
- Laboratorio Clínico de Especialidades del Hospital General ISSSTE, Av. Universidad 410, Aguascalientes CP 20010, Ags, Mexico;
| | - Marcelo Silva-Briano
- Laboratorio de Ecología, Departamento de Biología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
| | - Alma Lilián Guerrero-Barrera
- Laboratorio de Biología Celular y Tisular, Departamento de Morfología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
- Correspondence: (A.L.G.-B.); (J.J.S.-R.)
| | - José Jesús Sigala-Rodríguez
- Colección Zoológica, Departamento de Biología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Aguascalientes CP 20131, Ags, Mexico;
- Correspondence: (A.L.G.-B.); (J.J.S.-R.)
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5
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Seneci L, Zdenek CN, Bourke LA, Cochran C, Sánchez EE, Neri-Castro E, Bénard-Valle M, Alagón A, Frank N, Fry BG. A symphony of destruction: Dynamic differential fibrinogenolytic toxicity by rattlesnake (Crotalus and Sistrurus) venoms. Comp Biochem Physiol C Toxicol Pharmacol 2021; 245:109034. [PMID: 33766656 PMCID: PMC8162888 DOI: 10.1016/j.cbpc.2021.109034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 03/02/2021] [Accepted: 03/15/2021] [Indexed: 12/15/2022]
Abstract
What factors influence the evolution of a heavily selected functional trait in a diverse clade? This study adopts rattlesnakes as a model group to investigate the evolutionary history of venom coagulotoxicity in the wider context of phylogenetics, natural history, and biology. Venom-induced clotting of human plasma and fibrinogen was determined and mapped onto the rattlesnake phylogenetic tree to reconstruct the evolution of coagulotoxicity across the group. Our results indicate that venom phenotype is often independent of phylogenetic relationships in rattlesnakes, suggesting the importance of diet and/or other environmental variables in driving venom evolution. Moreover, the striking inter- and intraspecific variability in venom activity on human blood highlights the considerable variability faced by physicians treating envenomation. This study is the most comprehensive effort to date to describe and characterize the evolutionary and biological aspects of coagulotoxins in rattlesnake venom. Further research at finer taxonomic levels is recommended to elucidate patterns of variation within species and lineages.
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Affiliation(s)
- Lorenzo Seneci
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia; Institute of Biology Leiden (IBL), Leiden University, 2333 BE Leiden, the Netherlands
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Lachlan A Bourke
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
| | - Chip Cochran
- Department of Earth and Biological Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Elda E Sánchez
- National Natural Toxins Research Center (NNTRC), Department of Chemistry, Texas A&M University-Kingsville, MSC 224, 975 West Avenue B, Kingsville, TX 78363, USA
| | - Edgar Neri-Castro
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Melisa Bénard-Valle
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | - Alejandro Alagón
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnologa, Universidad Nacional Autónoma de México, Av. Universidad 2001, Cuernavaca, Morelos 62210, Mexico
| | | | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia.
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6
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Crowell HL, King KC, Whelan JM, Harmel MV, Garcia G, Gonzales SG, Maier PH, Neldner H, Nhu T, Nolan JT, Taylor EN. Thermal ecology and baseline energetic requirements of a large-bodied ectotherm suggest resilience to climate change. Ecol Evol 2021; 11:8170-8182. [PMID: 34188878 PMCID: PMC8216919 DOI: 10.1002/ece3.7649] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 11/12/2022] Open
Abstract
Most studies on how rising temperatures will impact terrestrial ectotherms have focused on single populations or multiple sympatric species. Addressing the thermal and energetic implications of climatic variation on multiple allopatric populations of a species will help us better understand how a species may be impacted by altered climates.We used eight years of thermal and behavioral data collected from four populations of Pacific rattlesnakes (Crotalus oreganus) living in climatically distinct habitat types (inland and coastal) to determine the field-active and laboratory-preferred body temperatures, thermoregulatory metrics, and maintenance energetic requirements of snakes from each population.Physical models showed that thermal quality was best at coastal sites, but inland snakes thermoregulated more accurately despite being in more thermally constrained environments. Projected increases of 1 and 2°C in ambient temperature result in an increase in overall thermal quality at both coastal and inland sites.Population differences in modeled standard metabolic rate estimates were driven by body size and not field-active body temperature, with inland snakes requiring 1.6× more food annually than coastal snakes.All snakes thermoregulated with high accuracy, suggesting that small increases in ambient temperature are unlikely to impact the maintenance energetic requirements of individual snakes and that some species of large-bodied reptiles may be robust to modest thermal perturbations under conservative climate change predictions. .
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Affiliation(s)
- Hayley L. Crowell
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
- Ecology and Evolutionary Biology DepartmentUniversity of MichiganAnn ArborMIUSA
| | - Katherine C. King
- Crocodile Lake Wildlife RefugeU.S. Fish and Wildlife ServiceKey LargoFLUSA
| | - James M. Whelan
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | | | - Gennesee Garcia
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - Sebastian G. Gonzales
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - Paul H. Maier
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - Heather Neldner
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - Thomas Nhu
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - John T. Nolan
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
| | - Emily N. Taylor
- Biological Sciences DepartmentCalifornia Polytechnic State UniversitySan Luis ObispoCAUSA
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7
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Seneci L, Zdenek CN, Chowdhury A, Rodrigues CFB, Neri-Castro E, Bénard-Valle M, Alagón A, Fry BG. A Clot Twist: Extreme Variation in Coagulotoxicity Mechanisms in Mexican Neotropical Rattlesnake Venoms. Front Immunol 2021; 12:612846. [PMID: 33815366 PMCID: PMC8011430 DOI: 10.3389/fimmu.2021.612846] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/11/2021] [Indexed: 12/11/2022] Open
Abstract
Rattlesnakes are a diverse clade of pit vipers (snake family Viperidae, subfamily Crotalinae) that consists of numerous medically significant species. We used validated in vitro assays measuring venom-induced clotting time and strength of any clots formed in human plasma and fibrinogen to assess the coagulotoxic activity of the four medically relevant Mexican rattlesnake species Crotalus culminatus, C. mictlantecuhtli, C. molossus, and C. tzabcan. We report the first evidence of true procoagulant activity by Neotropical rattlesnake venom in Crotalus culminatus. This species presented a strong ontogenetic coagulotoxicity dichotomy: neonates were strongly procoagulant via Factor X activation, whereas adults were pseudo-procoagulant in that they converted fibrinogen into weak, unstable fibrin clots that rapidly broke down, thereby likely contributing to net anticoagulation through fibrinogen depletion. The other species did not activate clotting factors or display an ontogenetic dichotomy, but depleted fibrinogen levels by cleaving fibrinogen either in a destructive (non-clotting) manner or via a pseudo-procoagulant mechanism. We also assessed the neutralization of these venoms by available antivenom and enzyme-inhibitors to provide knowledge for the design of evidence-based treatment strategies for envenomated patients. One of the most frequently used Mexican antivenoms (Bioclon Antivipmyn®) failed to neutralize the potent procoagulant toxic action of neonate C. culminatus venom, highlighting limitations in snakebite treatment for this species. However, the metalloprotease inhibitor Prinomastat substantially thwarted the procoagulant venom activity, while 2,3-dimercapto-1-propanesulfonic acid (DMPS) was much less effective. These results confirm that venom-induced Factor X activation (a procoagulant action) is driven by metalloproteases, while also suggesting Prinomastat as a more promising potential adjunct treatment than DMPS for this species (with the caveat that in vivo studies are necessary to confirm this potential clinical use). Conversely, the serine protease inhibitor 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) inhibited the direct fibrinogen cleaving actions of C. mictlantecuhtli venom, thereby revealing that the pseudo-procoagulant action is driven by kallikrein-type serine proteases. Thus, this differential ontogenetic variation in coagulotoxicity patterns poses intriguing questions. Our results underscore the need for further research into Mexican rattlesnake venom activity, and also highlights potential limitations of current antivenom treatments.
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Affiliation(s)
- Lorenzo Seneci
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Institute of Biology Leiden (IBL), Leiden University, Leiden, Netherlands
| | - Christina N Zdenek
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
| | - Abhinandan Chowdhury
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Department of Biochemistry and Microbiology, North South University, Dhaka, Bangladesh
| | - Caroline F B Rodrigues
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia.,Laboratório de Herpetologia, Instituto Butantan, São Paulo, Brazil
| | - Edgar Neri-Castro
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Melisa Bénard-Valle
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Alejandro Alagón
- Instituto de Biotecnología, Universidad Autónoma de México, Cuernavaca, Mexico
| | - Bryan G Fry
- Venom Evolution Lab, School of Biological Sciences, University of Queensland, St Lucia, QLD, Australia
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8
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Holding ML, Sovic MG, Colston TJ, Gibbs HL. The scales of coevolution: comparative phylogeography and genetic demography of a locally adapted venomous predator and its prey. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Abstract
Coevolutionary theory predicts that differences in the genetic demography of interacting species can influence patterns of local adaptation by affecting the potential of local populations to respond to selection. We conducted a comparative phylogeographical study of venomous rattlesnakes and their venom-resistant ground squirrel prey across California, and assessed how effective population size (Ne) estimates correspond with a previously documented pattern of rattlesnake local adaptation. Using RAD sequencing markers, we detected lineage relationships among both the rattlesnakes (Crotalus oreganus ssp.) and ground squirrels (Otospermophilus sp.) that are incongruent with previous phylogenetic hypotheses. Both rattlesnakes and squirrels share a deep divergence at the Sacramento–San Joaquin River Delta. At this broad phylogeographical scale, we found that the locally adapted rattlesnakes had higher Ne than squirrels. At the population scale, snakes also had larger Ne accompanied by larger values of several metrics of population genetic diversity. However, the specific magnitude of local adaptation of venom activity to ground squirrel venom resistance was not significantly correlated with local differences in Ne or other diversity statistics between predator and prey populations, suggesting that other factors in the geographic mosaic of coevolution contribute to the specific local-scale outcomes of this interaction. These results suggest an evolutionary mechanism that may explain some (but clearly not all) of rattlesnake local adaptation in this coevolutionary interaction – larger population sizes raise the adaptive potential of rattlesnakes compared to ground squirrels.
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Affiliation(s)
- Matthew L Holding
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Michael G Sovic
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
| | - Timothy J Colston
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - H Lisle Gibbs
- Department of Evolution, Ecology, and Organismal Biology, Ohio State University, Columbus, OH, USA
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9
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Ceríaco LMP, Tolley KA, Marques MP, Heinicke MP, Bauer AM. A dwarf among giants: phylogenetic position of the elusive Angolan Adder (Bitis heraldica) and biogeographic affinities of Angolan Afromontane regions. AFR J HERPETOL 2020. [DOI: 10.1080/21564574.2020.1782484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Luis MP Ceríaco
- Museu de História Natural e da Ciência da Universidade do Porto, Praça Gomes Teixeira, Porto, Portugal
- Departamento de Zoologia e Antropologia (Museu Bocage), Museu Nacional de História Natural e da Ciência, Universidade de Lisboa, Rua da Escola Politécnica, Lisboa, Portugal
| | - Krystal A Tolley
- South African National Biodiversity Institute, Kirstenbosch Research Centre, Cape Town, South Africa
- Centre for Ecological Genomics and Wildlife Conservation, University of Johannesburg, Auckland Park, Johannesburg, South Africa
| | - Mariana P Marques
- Departamento de Zoologia e Antropologia (Museu Bocage), Museu Nacional de História Natural e da Ciência, Universidade de Lisboa, Rua da Escola Politécnica, Lisboa, Portugal
- Research Center in Biodiversity and Genetic Resources (CIBIO), Research Network in Biodiversity and Evolutionary Biology (InBIO), University of Porto, Rua Padre Armando Quintas 7, Vairão, Porto, Portugal
| | - Matthew P Heinicke
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan, USA
| | - Aaron M Bauer
- Department of Biology and Center for Biodiversity and Ecosystem Stewardship, Villanova University, Villanova, Pennsylvania, USA
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10
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Keyler DE, Saini V, O’Shea M, Gee J, Smith CF, Mackessy SP. Crotalus oreganus concolor: Envenomation Case with Venom Analysis and a Diagnostic Conundrum of Myoneurologic Symptoms. Wilderness Environ Med 2020; 31:220-225. [DOI: 10.1016/j.wem.2019.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 12/01/2019] [Accepted: 12/09/2019] [Indexed: 10/24/2022]
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11
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Harvey JA, Larsen KW. Rattlesnake migrations and the implications of thermal landscapes. MOVEMENT ECOLOGY 2020; 8:21. [PMID: 32514356 PMCID: PMC7251723 DOI: 10.1186/s40462-020-00202-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND The importance of thermal resources to terrestrial ectotherms has been well documented but less often considered in larger-scale analyses of habitat use and selection, such as those routinely conducted using standard habitat features such as vegetation and physical structure. Selection of habitat based on thermal attributes may be of particular importance for ectothermic species, especially in colder climates. In Canada, Western Rattlesnakes (Crotalus oreganus) reach their northern limits, with limited time to conduct annual migratory movements between hibernacula and summer habitat. We radio-tracked 35 male snakes departing from 10 different hibernacula. We examined coarse-scale differences in migratory movements across the region, and then compared the route of each snake with thermal landscapes and ruggedness GIS maps generated for different periods of the animals' active season. RESULTS We observed dichotomous habitat use (grasslands versus upland forests) throughout most of the species' northern range, reflected in different migratory movements of male snakes emanating from different hibernacula. Snakes utilizing higher-elevation forests moved further during the course of their annual migrations, and these snakes were more likely to use warmer areas of the landscape. CONCLUSION In addition to thermal benefits, advantages gained from selective migratory patterns may include prey availability and outbreeding. Testing these alternative hypotheses was beyond the scope of this study, and to collect the data to do so will require overcoming certain challenges. Still, insight into migratory differences between rattlesnake populations and the causal mechanism(s) of migrations will improve our ability to assess the implications of landscape change, management, and efficacy of conservation planning. Our findings suggest that such assessments may need to be tailored to individual dens and the migration strategies of their inhabitants. Additionally, local and landscape-scale migration patterns, as detected in this study, will have repercussions for snakes under climate-induced shifts in ecosystem boundaries and thermal regimes.
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Affiliation(s)
- Jessica A. Harvey
- Environmental Science Program, Thompson Rivers University, Kamloops, Canada
- Victoria, Canada
| | - Karl W. Larsen
- Department of Natural Resource Science, Thompson Rivers University, 805 TRU Way, Kamloops, British Columbia V2C 0C8 Canada
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Parsons SB, Peterson CR, Jenkins CL, Matocq MD. Gene Flow and Habitat Connectivity in a Native Rattlesnake Population on the Snake River Plain. WEST N AM NATURALIST 2019. [DOI: 10.3398/064.079.0308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Susan B. Parsons
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209
| | - Charles R. Peterson
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83209
| | | | - Marjorie D. Matocq
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89557
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13
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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] [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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14
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DNA barcodes from snake venom: a broadly applicable method for extraction of DNA from snake venoms. Biotechniques 2018; 65:339-345. [PMID: 30477329 DOI: 10.2144/btn-2018-0096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
DNA barcoding is a simple technique used to develop a large-scale system of classification that is broadly applicable across a wide variety of taxa. DNA-based analysis of snake venoms can provide a system of classification independent of currently accepted taxonomic relationships by generating DNA barcodes specific to each venom sample. DNA purification from dried snake venoms has previously required large amounts of starting material, has resulted in low yields and inconsistent amplification, and was possible with front-fanged snakes only. Here, we present a modified DNA extraction protocol applied to venoms of both front- and rear-fanged snakes that requires significantly less starting material (1 mg) and yields sufficient amounts of DNA for successful PCR amplification of regions commonly used for DNA barcoding. [Formula: see text].
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15
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Holding ML, Margres MJ, Rokyta DR, Gibbs HL. Local prey community composition and genetic distance predict venom divergence among populations of the northern Pacific rattlesnake (
Crotalus oreganus
). J Evol Biol 2018; 31:1513-1528. [DOI: 10.1111/jeb.13347] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 06/23/2018] [Accepted: 06/28/2018] [Indexed: 01/15/2023]
Affiliation(s)
- Matthew L. Holding
- Department of Evolution, Ecology, and Organismal Biology The Ohio State University Columbus OH USA
- Department of Biological Sciences Florida State University Tallahassee FL USA
| | - Mark J. Margres
- Department of Biological Sciences Florida State University Tallahassee FL USA
| | - Darin R. Rokyta
- Department of Biological Sciences Florida State University Tallahassee FL USA
| | - H. Lisle Gibbs
- Department of Evolution, Ecology, and Organismal Biology The Ohio State University Columbus OH USA
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16
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Species limits in the Morelet’s Alligator lizard (Anguidae: Gerrhonotinae). Mol Phylogenet Evol 2018; 120:16-27. [DOI: 10.1016/j.ympev.2017.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 09/21/2017] [Accepted: 11/27/2017] [Indexed: 11/22/2022]
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17
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O'Connell KA, Streicher JW, Smith EN, Fujita MK. Geographical features are the predominant driver of molecular diversification in widely distributed North American whipsnakes. Mol Ecol 2017; 26:5729-5751. [PMID: 28802078 DOI: 10.1111/mec.14295] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 07/17/2017] [Accepted: 07/24/2017] [Indexed: 01/08/2023]
Abstract
Allopatric divergence following the formation of geographical features has been implicated as a major driver of evolutionary diversification. Widespread species complexes provide opportunities to examine allopatric divergence across varying degrees of isolation in both time and space. In North America, several geographical features may play such a role in diversification, including the Mississippi River, Pecos River, Rocky Mountains, Cochise Filter Barrier, Gulf of California and Isthmus of Tehuantepec. We used thousands of nuclear single nucleotide polymorphisms (SNPs) and mitochondrial DNA from several species of whipsnakes (genera Masticophis and Coluber) distributed across North and Central America to investigate the role that these geographical features have played on lineage divergence. We hypothesize that these features restrict gene flow and separate whipsnakes into diagnosable genomic clusters. We performed genomic clustering and phylogenetic reconstructions at the species and population levels using Bayesian and likelihood analyses and quantified migration levels across geographical features to assess the degree of genetic isolation due to allopatry. Our analyses suggest that (i) major genetic divisions are often consistent with isolation by geographical features, (ii) migration rates between clusters are asymmetrical across major geographical features, and (iii) areas that receive proportionally more migrants possess higher levels of genetic diversity. Collectively, our findings suggest that multiple features of the North American landscape contributed to allopatric divergence in this widely distributed snake group.
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Affiliation(s)
- Kyle A O'Connell
- Department of Biology, The University of Texas at Arlington, Arlington, TX, USA.,The Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA
| | | | - Eric N Smith
- Department of Biology, The University of Texas at Arlington, Arlington, TX, USA.,The Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA
| | - Matthew K Fujita
- Department of Biology, The University of Texas at Arlington, Arlington, TX, USA.,The Amphibian and Reptile Diversity Research Center, University of Texas at Arlington, Arlington, TX, USA
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18
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Suntrarachun S, Chanhome L, Sumontha M. Phylogenetic analysis of the king cobra, Ophiophagus hannah in Thailand based on mitochondrial DNA sequences. ASIAN BIOMED 2017. [DOI: 10.5372/1905-7415.0802.289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Abstract
Background: Snakes possess adaptive characteristics of morphology that may result in incorrect reconstruction of phylogeny. Molecular approaches have become the major source of new information for advancing our understanding of evolutionary, genetic relationships, and species identification.
Objective: We studied DNA sequences of Ophiophagus hannah in different parts of Thailand and compared them with those of O. hannah from other countries.
Materials and Methods: We studied the mitochondrial NADH dehydrogenase subunit 2 (ND2) and control region (CR) sequences of 12 individuals O. hannah from different localities across Thailand. Phylogenetic analysis of DNA sequences were compared to the published sequences of O. hannah deposited in NCBI GenBank database from other countries.
Results: O. hannah could be categorized into 2 Clades, 5 haplotypes, and 4 localities based on 43 different nucleotide positions from the 736 bp of ND2 and 673 bp of CR. Clade A was haplotype A from southern Thailand. Clade B consisted of haplotypes B, C, D, and E. Haplotype B and C came from northern Thailand. Haplotype D came from western Thailand, while haplotype E was O. hannah from central Thailand. The DNA sequences of Clade B were similar to the sequences of O. hannah in Myanmar and southern China that are already deposited in NCBI GenBank database.
Conclusion: We found a different genotype of O. hannah from southern Thailand and suggest that this may be a new species of O. hannah.
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Affiliation(s)
- Sunutcha Suntrarachun
- Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok 10330, Thailand
| | - Lawan Chanhome
- Queen Saovabha Memorial Institute, The Thai Red Cross Society, Bangkok 10330, Thailand
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19
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Almeida J, Resende L, Silva A, Ribeiro R, Stábeli R, Soares A, Calderon L, Marangoni S, Da Silva S. Biochemical and functional studies of ColTx-I, a new myotoxic phospholipase A2 isolated from Crotalus oreganus lutosus (Great Basin rattlesnake) snake venom. Toxicon 2016; 117:1-12. [DOI: 10.1016/j.toxicon.2016.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 03/05/2016] [Accepted: 03/15/2016] [Indexed: 01/13/2023]
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20
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Diversity-dependent cladogenesis throughout western Mexico: Evolutionary biogeography of rattlesnakes (Viperidae: Crotalinae: Crotalus and Sistrurus). Mol Phylogenet Evol 2016; 97:145-154. [DOI: 10.1016/j.ympev.2015.12.020] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/15/2015] [Accepted: 12/30/2015] [Indexed: 11/22/2022]
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21
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Davis MA, Douglas MR, Collyer ML, Douglas ME. Deconstructing a Species-Complex: Geometric Morphometric and Molecular Analyses Define Species in the Western Rattlesnake (Crotalus viridis). PLoS One 2016; 11:e0146166. [PMID: 26816132 PMCID: PMC4731396 DOI: 10.1371/journal.pone.0146166] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 12/13/2015] [Indexed: 11/23/2022] Open
Abstract
Morphological data are a conduit for the recognition and description of species, and their acquisition has recently been broadened by geometric morphometric (GM) approaches that co-join the collection of digital data with exploratory 'big data' analytics. We employed this approach to dissect the Western Rattlesnake (Crotalus viridis) species-complex in North America, currently partitioned by mitochondrial (mt)DNA analyses into eastern and western lineages (two and seven subspecies, respectively). The GM data (i.e., 33 dorsal and 50 lateral head landmarks) were gleaned from 2,824 individuals located in 10 museum collections. We also downloaded and concatenated sequences for six mtDNA genes from the NCBI GenBank database. GM analyses revealed significant head shape differences attributable to size and subspecies-designation (but not their interactions). Pairwise shape distances among subspecies were significantly greater than those derived from ancestral character states via squared-change parsimony, with the greatest differences separating those most closely related. This, in turn, suggests the potential for historic character displacement as a diversifying force in the complex. All subspecies, save one, were significantly differentiated in a Bayesian discriminant function analysis (DFA), regardless of whether our priors were uniform or informative (i.e., mtDNA data). Finally, shape differences among sister-clades were significantly greater than expected by chance alone under a Brownian model of evolution, promoting the hypothesis that selection rather than drift was the driving force in the evolution of the complex. Lastly, we combine head shape and mtDNA data so as to derived an integrative taxonomy that produced robust boundaries for six OTUs (operational taxonomic units) of the C. viridis complex. We suggest these boundaries are concomitant with species-status and subsequently provide a relevant nomenclature for its recognition and representation.
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Affiliation(s)
- Mark A. Davis
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois Urbana Champaign, Champaign, IL, 61820, United States of America
| | - Marlis R. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, United States of America
| | - Michael L. Collyer
- Department of Biology, Western Kentucky University, Bowling Green, KY, 42101, United States of America
| | - Michael E. Douglas
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, United States of America
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22
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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] [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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23
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Torstrom SM, Pangle KL, Swanson BJ. Shedding subspecies: The influence of genetics on reptile subspecies taxonomy. Mol Phylogenet Evol 2014; 76:134-43. [DOI: 10.1016/j.ympev.2014.03.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 03/08/2014] [Accepted: 03/11/2014] [Indexed: 10/25/2022]
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24
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A novel phospholipase A2 (D49) from the venom of the Crotalus oreganus abyssus (North American Grand canyon rattlesnake). BIOMED RESEARCH INTERNATIONAL 2014; 2014:654170. [PMID: 24707493 PMCID: PMC3953673 DOI: 10.1155/2014/654170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 11/25/2013] [Accepted: 12/06/2013] [Indexed: 11/18/2022]
Abstract
Currently, Crotalus viridis was divided into two species: Crotalus viridis and Crotalus oreganus. The current classification divides "the old" Crotalus viridis into two new and independent species: Crotalus viridis (subspecies: viridis and nuntius) and Crotalus oreganus (subspecies: abyssus, lutosus, concolor, oreganus, helleri, cerberus, and caliginis). The analysis of a product from cDNA (E6d), derived from the gland of a specie Crotalus viridis viridis, was found to produce an acid phospholipase A2. In this study we isolated and characterized a PLA2 (D49) from Crotalus oreganus abyssus venom. Our studies show that the PLA2 produced from the cDNA of Crotalus viridis viridis (named E6d) is exactly the same PLA2 primary sequence of amino acids isolated from the venom of Crotalus oreganus abyssus. Thus, the PLA2 from E6d cDNA is actually the same PLA2 presented in the venom of Crotalus oreganus abyssus and does not correspond to the venom from Crotalus viridis viridis. These facts highlight the importance of performing more studies on subspecies of Crotalus oreganus and Crotalus viridis, since the old classification may have led to mixed results or mistaken data.
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25
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Putman BJ, Lind C, Taylor EN. Does Size Matter? Factors Influencing the Spatial Ecology of Northern Pacific Rattlesnakes(Crotalus oreganus oreganus) in Central California. COPEIA 2013. [DOI: 10.1643/ce-12-048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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26
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Grechko VV. The problems of molecular phylogenetics with the example of squamate reptiles: Mitochondrial DNA markers. Mol Biol 2013. [DOI: 10.1134/s0026893313010056] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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27
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Anderson CG, Greenbaum E. Phylogeography of Northern Populations of the Black-Tailed Rattlesnake (Crotalus molossus Baird And Girard, 1853), With the Revalidation of C. ornatus Hallowell, 1854. HERPETOLOGICAL MONOGRAPHS 2012. [DOI: 10.1655/herpmonographs-d-11-00012.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Barlow A, Grail W, de Bruyn M, Wüster W. Anonymous nuclear markers for the African adders (Serpentes: Viperidae: Bitis). CONSERV GENET RESOUR 2012. [DOI: 10.1007/s12686-012-9684-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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29
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Population genetic structure and geographic differentiation in the hot spring snake Thermophis baileyi (Serpentes, Colubridae): indications for glacial refuges in southern-central Tibet. Mol Phylogenet Evol 2012; 63:396-406. [PMID: 22306823 DOI: 10.1016/j.ympev.2012.01.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Revised: 01/10/2012] [Accepted: 01/17/2012] [Indexed: 11/21/2022]
Abstract
The endangered hot spring snake (Thermophis baileyi) is endemic to the Tibetan Plateau and restricted to a few sites at high altitudes (>3500 m a.s.l.). Its strong preference for habitats with hot springs might be an early adaptation to the cooling climate during the plateau uplift. Some of these thermal sites may have been free of ice during the last glacial maximum (LGM) serving as refuges for the snake. To test this and to examine the population genetic structure data of 12 microsatellites and mitochondrial DNA were obtained from 153 individuals from 12 sites across the plateau. Four of the microsatellite loci were newly developed for this study. The results suggest that T. baileyi has at least two genetically diverse clades in Tibet, which developed during the Pleistocene and expanded after the LGM. Accordingly, the existence of separate glacial refuges on the central plateau can be assumed. Analyses of the genetic variation indicated a high level of geographic differentiation and population structure on a regional as well as on a range-wide scale. The study shows that, apart from the phylogeographic signatures, the diversification of current Thermophis populations is caused by (a) a limited dispersal due to mountain ranges, (b) a strong preference for hot springs and (c) the insular distribution of suitable habitats on the plateau. The present data should be taken into account in necessary monitoring and management plans for T. baileyi.
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Lawing AM, Polly PD. Pleistocene climate, phylogeny, and climate envelope models: an integrative approach to better understand species' response to climate change. PLoS One 2011; 6:e28554. [PMID: 22164305 PMCID: PMC3229599 DOI: 10.1371/journal.pone.0028554] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 11/10/2011] [Indexed: 11/18/2022] Open
Abstract
Mean annual temperature reported by the Intergovernmental Panel on Climate Change increases at least 1.1°C to 6.4°C over the next 90 years. In context, a change in climate of 6°C is approximately the difference between the mean annual temperature of the Last Glacial Maximum (LGM) and our current warm interglacial. Species have been responding to changing climate throughout Earth's history and their previous biological responses can inform our expectations for future climate change. Here we synthesize geological evidence in the form of stable oxygen isotopes, general circulation paleoclimate models, species' evolutionary relatedness, and species' geographic distributions. We use the stable oxygen isotope record to develop a series of temporally high-resolution paleoclimate reconstructions spanning the Middle Pleistocene to Recent, which we use to map ancestral climatic envelope reconstructions for North American rattlesnakes. A simple linear interpolation between current climate and a general circulation paleoclimate model of the LGM using stable oxygen isotope ratios provides good estimates of paleoclimate at other time periods. We use geologically informed rates of change derived from these reconstructions to predict magnitudes and rates of change in species' suitable habitat over the next century. Our approach to modeling the past suitable habitat of species is general and can be adopted by others. We use multiple lines of evidence of past climate (isotopes and climate models), phylogenetic topology (to correct the models for long-term changes in the suitable habitat of a species), and the fossil record, however sparse, to cross check the models. Our models indicate the annual rate of displacement in a clade of rattlesnakes over the next century will be 2 to 3 orders of magnitude greater (430-2,420 m/yr) than it has been on average for the past 320 ky (2.3 m/yr).
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Affiliation(s)
- A Michelle Lawing
- Department of Geological Sciences, Indiana University, Bloomington, Indiana, United States of America.
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31
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Isolation and Characterization of a Natriuretic Peptide from Crotalus oreganus abyssus (Grand Canyon Rattlesnake) and its Effects on Systemic Blood Pressure and Nitrite Levels. Int J Pept Res Ther 2011. [DOI: 10.1007/s10989-011-9254-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Ferchaud AL, Lyet A, Cheylan M, Arnal V, Baron JP, Montgelard C, Ursenbacher S. High Genetic Differentiation Among French Populations of the Orsini’s Viper (Vipera ursinii ursinii) Based on Mitochondrial and Microsatellite Data: Implications for Conservation Management. J Hered 2010; 102:67-78. [DOI: 10.1093/jhered/esq098] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Lind CM, Husak JF, Eikenaar C, Moore IT, Taylor EN. The relationship between plasma steroid hormone concentrations and the reproductive cycle in the Northern Pacific rattlesnake, Crotalus oreganus. Gen Comp Endocrinol 2010; 166:590-9. [PMID: 20138180 DOI: 10.1016/j.ygcen.2010.01.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 11/15/2009] [Accepted: 01/31/2010] [Indexed: 11/22/2022]
Abstract
We describe the reproductive cycle of Northern Pacific rattlesnakes (Crotalus oreganus) by quantifying steroid hormone concentrations and observing reproductive behaviors in free-ranging individuals. Additionally, we examined reproductive tissues from museum specimens. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (March-October). We measured testosterone (T), 5alpha-dihydrotestosterone (DHT), and corticosterone (B) concentrations in both sexes and 17beta-estradiol (E2) and progesterone (P) in females only. We observed reproductive behaviors (e.g., consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections to relate steroid hormone concentrations to the timing of reproductive events. Our study revealed that C. oreganus in central California exhibits a bimodal pattern of breeding, with most mating behavior occurring in the spring and some incidences of mating behavior observed in late summer/fall. Each breeding period corresponded with elevated androgen (T or DHT) levels in males. Testes were regressed in the spring when the majority of reproductive behavior was observed in this population, and they reached peak volume in August and September during spermatogenesis. Although we did not detect seasonal variation in female hormone concentrations, some females had high E2 in the spring and fall, coincident with mating and with increased follicle size (indicating vitellogenesis) in museum specimens. Females with high E2 concentrations also had high T and DHT concentrations. Corticosterone concentrations in males and females were not related either to time of year or to concentrations of any other hormones quantified. Progesterone concentrations in females also did not vary seasonally, but this likely reflected sampling bias as females tended to be underground, and thus unobtainable, in summer months when P would be expected to be elevated during gestation. In females, P was positively correlated with T and DHT, and E2 was positively correlated with T.
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Affiliation(s)
- Craig M Lind
- Dept. Biological Sciences, California Polytechnic State University, San Luis Obispo, CA 93407-0401, USA.
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Evolutionary trends in venom composition in the western rattlesnakes (Crotalus viridis sensu lato): toxicity vs. tenderizers. Toxicon 2010; 55:1463-74. [PMID: 20227433 DOI: 10.1016/j.toxicon.2010.02.028] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 02/23/2010] [Accepted: 02/24/2010] [Indexed: 11/22/2022]
Abstract
The Western Rattlesnake (Crotalus viridis sensu lato, now including Crotalus oreganus) is broadly distributed across the western half of the United States, northwestern Mexico and southwestern Canada, and eight subspecies are currently recognized. Although some venom characteristics have been noted for most subspecies, a systematic study of venoms from all subspecies has not been reported. Venom was extracted from snakes collected from approximate geographic range centers for all subspecies and analyzed using SDS-PAGE, MALDI-TOF mass spectrometry, enzyme and toxicity assays. Electrophoretic and mass spectrometric analyses demonstrated that small myotoxins, disintegrins and PLA(2) were abundant in most venoms. PIII and PI metalloproteinases ( approximately 54 kDa and 23 kDa, respectively) were common to all venoms except C. o. concolor, C. o. caliginis and C.o. helleri. Metalloproteinase activity was highest in C. o. cerberus and lowest in C. o. concolor venoms ( approximately 100-fold difference). Conversely, C. o. concolor venom was the most toxic and C. o. cerberus venom was least toxic (15-fold difference). In general, venoms with high metalloproteinase activity were less toxic (type I venoms), while venoms which were highly toxic showed low protease activity (type II venoms). Within the C. viridis/oreganus complex, these two extremes of venom compositional phenotypes are observed, and it appears that high metalloproteinase activity and high toxicity are incompatible qualities of these venoms. The functional significance of these biochemical characteristics likely relates to characteristics of prey consumed, and venoms with low metalloproteinase activity may constrain snake prey selection or foraging activity patterns.
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Siegel DS, Sever DM, Rheubert JL, Gribbins KM. Reproductive Biology of Agkistrodon piscivorus Lacépède (Squamata, Serpentes, Viperidae, Crotalinae). HERPETOLOGICAL MONOGRAPHS 2009. [DOI: 10.1655/08-031.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Hamilton BT, Nowak EM. Relationships between Insolation and Rattlesnake Hibernacula. WEST N AM NATURALIST 2009. [DOI: 10.3398/064.069.0305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Barbanera F, Zuffi M, Guerrini M, Gentilli A, Tofanelli S, Fasola M, Dini F. Molecular phylogeography of the asp viper Vipera aspis (Linnaeus, 1758) in Italy: Evidence for introgressive hybridization and mitochondrial DNA capture. Mol Phylogenet Evol 2009; 52:103-14. [PMID: 19236928 DOI: 10.1016/j.ympev.2009.02.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 02/04/2009] [Accepted: 02/18/2009] [Indexed: 10/21/2022]
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Lin LH, Zhao Q, Ji X. Conservation genetics of the Chinese cobra (Naja atra) investigated with mitochondrial DNA sequences. Zoolog Sci 2009; 25:888-93. [PMID: 19267597 DOI: 10.2108/zsj.25.888] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We collected Chinese cobras (Naja atra) from one island (Dinghai) and four mainland (Huangshan, Lishui, Quanzhou, and Baise) populations in southeastern China, and used sequence data derived from the ND2 (1032 bp) and cytochrome b (1117 bp) genes and molecular variance estimates to investigate the population genetic structure of the species. Our sequence data show that: (1) the three eastern (Dinghai, Huangshan, and Lishui) populations are genetically segregated from the two southern (Quanzhou and Baise) populations; (2) the Quanzhou and Baise populations consist of two well-defined subclades, suggesting that the two populations have been well differentiated; (3) N. atra from the Huangshan population do not differ from those from the Lishui population, and lineage sorting in the northeastern part of the cobra's distributional range has not yet been completed because of the young age of Zhoushan Islands. The three eastern populations, the Quanzhou population, and the Baise population should be regarded as different management units (MUs). For these MUs, we suggest that in-situ protection measures should be taken because of their genetic uniqueness. Re-introductions or translocations are required to protect or re-establish natural populations of N. atra , but great care should be taken to enhance or retain local genetic variation.
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Affiliation(s)
- Long-Hui Lin
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210046, Jiangsu, China
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Meik JM, Pires-daSilva A. Evolutionary morphology of the rattlesnake style. BMC Evol Biol 2009; 9:35. [PMID: 19208237 PMCID: PMC2645363 DOI: 10.1186/1471-2148-9-35] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2008] [Accepted: 02/10/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The rattlesnake rattling system is an evolutionary novelty that includes anatomical, behavioral, and physiological modifications of the generalized pitviper tail. One such modification, the formation of a bony clublike style at the terminal region of the caudal vertebrae, has not previously been examined in a phylogenetic context. Here we used skeletal material, cleared and stained preparations, and radiographs of whole preserved specimens to examine interspecific variation in style morphology among 34 rattlesnake species. RESULTS Evolutionary Principal Components Analysis revealed an inverse relationship between caudal segmental counts and style size, supporting the hypothesis that bone from caudal vertebral elements was reallocated to style formation during the evolution of this structure. Most of the basal rattlesnake species have small styles consisting of few compacted vertebral elements; however, early in the rattlesnake radiation there appears to have been two independent transitions to relatively large, pronged styles consisting of multiple coalesced vertebrae (once in Sistrurus catenatus, and once in Crotalus following the divergence of the Mexican long-tailed rattlesnakes). In terms of style shape, the two most divergent species, C. catalinensis and C. ericsmithi, provide insight into the possible relationship between style and rattle matrix morphology and lineage-specific evolutionary strategies for retaining rattle segments. CONCLUSION The considerable interspecific variation in rattle morphology appears to correspond to variation in the bony style. We hypothesize that style morphology evolves indirectly as an integrated module responding to adaptive evolution on matrix morphology.
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Affiliation(s)
- Jesse M Meik
- Department of Biology, The University of Texas at Arlington, Arlington, TX, USA.
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Beheregaray LB. Twenty years of phylogeography: the state of the field and the challenges for the Southern Hemisphere. Mol Ecol 2008; 17:3754-74. [PMID: 18627447 DOI: 10.1111/j.1365-294x.2008.03857.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phylogeography is a young, vigorous and integrative field of study that uses genetic data to understand the history of populations. This field has recently expanded into many areas of biology and also into several historical disciplines of Earth sciences. In this review, I present a numerical synthesis of the phylogeography literature based on an examination of over 3000 articles published during the first 20 years of the field (i.e. from 1987 to 2006). Information from several topics needed to evaluate the progress, tendencies and deficiencies of the field is summarized for 10 major groups of organisms and at a global scale. The topics include the geography of phylogeographic surveys, comparative nature of studies, temporal scales and major environments investigated, and genetic markers used. I also identify disparities in research productivity between the developing and the developed world, and propose ways to reduce some of the challenges faced by phylogeographers from less affluent countries. Phylogeography has experienced explosive growth in recent years fuelled by developments in DNA technology, theory and statistical analysis. I argue that the intellectual maturation of the field will eventually depend not only on these recent developments, but also on syntheses of comparative information across different regions of the globe. For this to become a reality, many empirical phylogeographic surveys in regions of the Southern Hemisphere (and in developing countries of the Northern Hemisphere) are needed. I expect the information and views presented here will assist in promoting international collaborative work in phylogeography and in guiding research efforts at both regional and global levels.
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Affiliation(s)
- Luciano B Beheregaray
- Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
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Glaudas X, Jezkova T, Rodríguez-Robles JA. Feeding ecology of the Great Basin Rattlesnake (Crotalus lutosus, Viperidae). CAN J ZOOL 2008. [DOI: 10.1139/z08-049] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Documenting variation in organismal traits is essential to understanding the ecology of natural populations. We relied on stomach contents of preserved specimens and literature records to assess ontogenetic, intersexual, temporal, and geographic variations in the feeding ecology of the North American Great Basin Rattlesnake ( Crotalus lutosus Klauber, 1930). Snakes preyed mainly on rodents, occasionally on lizards, and less frequently on birds; squamate eggs and frogs were rarely eaten. There was a positive relationship between predator and prey size. The best predictors of this relationship were prey diameter as a function of snake body length and head size, underscoring the importance of prey diameter for gape-limited predators such as snakes. Crotalus lutosus displayed ontogenetic, sexual, and seasonal variations in diet. Smaller rattlesnakes fed predominantly on lizards, whereas larger individuals mostly fed on mammals. Females fed on lizards more often than males. The proportion of mammals in the diet was highest during the summer, a temporal variation that may be related to behavioral shifts in the diel activity and prey selectivity of C. lutosus, and (or) to differential abundance of rodents between seasons. Great Basin Rattlesnakes also displayed geographic variation in feeding habits, with snakes from the Great Basin Desert eating a higher proportion of lizards than serpents from the more northern Columbia Plateau.
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Affiliation(s)
- Xavier Glaudas
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA
| | - Tereza Jezkova
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA
| | - Javier A. Rodríguez-Robles
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154-4004, USA
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Fontanella FM, Feldman CR, Siddall ME, Burbrink FT. Phylogeography of Diadophis punctatus: Extensive lineage diversity and repeated patterns of historical demography in a trans-continental snake. Mol Phylogenet Evol 2008; 46:1049-70. [DOI: 10.1016/j.ympev.2007.10.017] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2007] [Revised: 10/09/2007] [Accepted: 10/14/2007] [Indexed: 11/28/2022]
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Phylogeography and species boundaries of the western North American Nightsnake (Hypsiglena torquata): Revisiting the subspecies concept. Mol Phylogenet Evol 2008; 46:1095-115. [DOI: 10.1016/j.ympev.2007.12.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 11/26/2007] [Accepted: 12/04/2007] [Indexed: 11/21/2022]
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Leaché AD, Mulcahy DG. Phylogeny, divergence times and species limits of spiny lizards (Sceloporus magister species group) in western North American deserts and Baja California. Mol Ecol 2007; 16:5216-33. [PMID: 17944851 DOI: 10.1111/j.1365-294x.2007.03556.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The broad distribution of the Sceloporus magister species group (squamata: phrynosomatidae) throughout western North America provides an appropriate model for testing biogeographical hypotheses explaining the timing and origins of diversity across mainland deserts and the Baja California Peninsula. We inferred concordant phylogenetic trees describing the higher-level relationships within the magister group using 1.6 kb of mitochondrial DNA (mtDNA) and 1.7 kb of nuclear DNA data. These data provide strong support for the parallel divergence of lineages endemic to the Baja California Peninsula (S. zosteromus and the orcutti complex) in the form of two sequential divergence events at the base of the magister group phylogeny. A relaxed phylogenetic analysis of the mtDNA data using one fossil and one biogeographical constraint provides a chronology of these divergence events and evidence that further diversification within the Baja California clades occurred simultaneously, although patterns of geographical variation and speciation between clades differ. We resolved four major phylogeographical clades within S. magister that (i) provide a novel phylogenetic placement of the Chihuahuan Desert populations sister to the Mojave Desert; (ii) illustrate a mixed history for the Colorado Plateau that includes Mojave and Sonoran Desert components; and (iii) identify an area of overlap between the Mojave and Sonoran Desert clades near Yuma, Arizona. Estimates of bidirectional migration rates among populations of S. magister using four nuclear loci support strong asymmetries in gene flow among the major mtDNA clades. Based on the nonexclusivity of mtDNA haplotypes, nuclear gene flow among populations and wide zones of phenotypic intergradation, S. magister appears to represent a single geographically variable and widespread species.
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Affiliation(s)
- Adam D Leaché
- Museum of Vertebrate Zoology and Department of Integrative Biology, 3101 Valley Life Sciences Building, University of California, Berkeley, CA 94720 3160, USA.
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Lukoschek V, Waycott M, Marsh H. Phylogeography of the olive sea snake, Aipysurus laevis (Hydrophiinae) indicates Pleistocene range expansion around northern Australia but low contemporary gene flow. Mol Ecol 2007; 16:3406-22. [PMID: 17688542 DOI: 10.1111/j.1365-294x.2007.03392.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pleistocene sea-level fluctuations profoundly changed landmass configurations around northern Australia. The cyclic emergence of the Torres Strait land bridge and concomitant shifts in the distribution of shallow-water marine habitats repeatedly sundered east and west coast populations. These biogeographical perturbations invoke three possible scenarios regarding the directions of interglacial range expansion: west to east, east to west, or bidirectional. We evaluated these scenarios for the olive sea snake, Aipysurus laevis, by exploring its genetic structure around northern Australia based on 354 individuals from 14 locations in three regions (Western Australia, WA; Gulf of Carpentaria, GoC; Great Barrier Reef, GBR). A 726-bp fragment of the mitochondrial DNA ND4 region revealed 41 variable sites and 38 haplotypes, with no shared haplotypes among the three regions. Population genetic structure was strong overall, phiST=0.78, P<0.001, and coalescent analyses revealed no migration between regions. Genetic diversity was low in the GBR and GoC and the genetic signatures of these regions indicated range or population expansions consistent with their recent marine transgressions around 7000 years ago. By contrast, genetic diversity on most WA reefs was higher and there were no signals of recent expansion events on these reefs. Phylogenetic analyses indicated that GBR and GoC haplotypes were derived from WA haplotypes; however, statistical parsimony suggested that recent range expansion in the GBR-GoC probably occurred from east coast populations, possibly in the Coral Sea. Levels of contemporary female-mediated gene flow varied within regions and reflected potential connectivity among populations afforded by the different regional habitat types.
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Affiliation(s)
- V Lukoschek
- School of Marine and Tropical Biology, James Cook University, Townsville, Qld 4811, Australia.
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Comparative mitochondrial genomics of snakes: extraordinary substitution rate dynamics and functionality of the duplicate control region. BMC Evol Biol 2007; 7:123. [PMID: 17655768 PMCID: PMC1950710 DOI: 10.1186/1471-2148-7-123] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Accepted: 07/26/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The mitochondrial genomes of snakes are characterized by an overall evolutionary rate that appears to be one of the most accelerated among vertebrates. They also possess other unusual features, including short tRNAs and other genes, and a duplicated control region that has been stably maintained since it originated more than 70 million years ago. Here, we provide a detailed analysis of evolutionary dynamics in snake mitochondrial genomes to better understand the basis of these extreme characteristics, and to explore the relationship between mitochondrial genome molecular evolution, genome architecture, and molecular function. We sequenced complete mitochondrial genomes from Slowinski's corn snake (Pantherophis slowinskii) and two cottonmouths (Agkistrodon piscivorus) to complement previously existing mitochondrial genomes, and to provide an improved comparative view of how genome architecture affects molecular evolution at contrasting levels of divergence. RESULTS We present a Bayesian genetic approach that suggests that the duplicated control region can function as an additional origin of heavy strand replication. The two control regions also appear to have different intra-specific versus inter-specific evolutionary dynamics that may be associated with complex modes of concerted evolution. We find that different genomic regions have experienced substantial accelerated evolution along early branches in snakes, with different genes having experienced dramatic accelerations along specific branches. Some of these accelerations appear to coincide with, or subsequent to, the shortening of various mitochondrial genes and the duplication of the control region and flanking tRNAs. CONCLUSION Fluctuations in the strength and pattern of selection during snake evolution have had widely varying gene-specific effects on substitution rates, and these rate accelerations may have been functionally related to unusual changes in genomic architecture. The among-lineage and among-gene variation in rate dynamics observed in snakes is the most extreme thus far observed in animal genomes, and provides an important study system for further evaluating the biochemical and physiological basis of evolutionary pressures in vertebrate mitochondria.
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