Evidence for divergent patterns of local selection driving venom variation in Mojave Rattlesnakes (Crotalus scutulatus).

Autor: Strickland JL; Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL, 32816, USA.; Department of Biological Sciences, Clemson Univeristy, 190 Collings St., Clemson, SC, 29634, USA., Smith CF; School of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA., Mason AJ; Department of Biological Sciences, Clemson University, 190 Collings St., Clemson, SC, 29634, USA., Schield DR; Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76010, USA., Borja M; Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad s/n. Fracc. Filadelfia, C.P. 35070, Gómez Palacio, Dgo., Mexico., Castañeda-Gaytán G; Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango, Av. Universidad s/n. Fracc. Filadelfia, C.P. 35070, Gómez Palacio, Dgo., Mexico., Spencer CL; Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA., Smith LL; Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA., Trápaga A; Museum of Vertebrate Zoology, University of California, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA., Bouzid NM; Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Box 351800, Seattle, WA, 98195, USA., Campillo-García G; Museo de Zoología, Department of Evolutionary Biology, Faculta de Ciencias, Universidad Nacional Autónoma de México, External Circuit of Ciudad Universitaria, México City, Mexico., Flores-Villela OA; Museo de Zoología, Department of Evolutionary Biology, Faculta de Ciencias, Universidad Nacional Autónoma de México, External Circuit of Ciudad Universitaria, México City, Mexico., Antonio-Rangel D; Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Laboratorio de Cordados Terrestres, Colección Herpetológica, Del. Miguel Hidalgo, México City, Mexico., Mackessy SP; School of Biological Sciences, University of Northern Colorado, 501 20th Street, Greeley, CO, 80639, USA., Castoe TA; Department of Biology, University of Texas at Arlington, 501 S. Nedderman Drive, Arlington, TX, 76010, USA., Rokyta DR; Department of Biological Science, Florida State University, Tallahassee, Florida, 32306, USA., Parkinson CL; Department of Biology, University of Central Florida, 4110 Libra Drive, Orlando, FL, 32816, USA. viper@clemson.edu.; Department of Biological Sciences & Department of Forestry and Environmental Conservation, Clemson University, 190 Collings St., Clemson, SC, 29634, USA. viper@clemson.edu.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2018 Dec 04; Vol. 8 (1), pp. 17622. Date of Electronic Publication: 2018 Dec 04.
DOI: 10.1038/s41598-018-35810-9
Abstrakt: Snake venoms represent an enriched system for investigating the evolutionary processes that lead to complex and dynamic trophic adaptations. It has long been hypothesized that natural selection may drive geographic variation in venom composition, yet previous studies have lacked the population genetic context to examine these patterns. We leverage range-wide sampling of Mojave Rattlesnakes (Crotalus scutulatus) and use a combination of venom, morphological, phylogenetic, population genetic, and environmental data to characterize the striking dichotomy of neurotoxic (Type A) and hemorrhagic (Type B) venoms throughout the range of this species. We find that three of the four previously identified major lineages within C. scutulatus possess a combination of Type A, Type B, and a 'mixed' Type A + B venom phenotypes, and that fixation of the two main venom phenotypes occurs on a more fine geographic scale than previously appreciated. We also find that Type A + B individuals occur in regions of inferred introgression, and that this mixed phenotype is comparatively rare. Our results support strong directional local selection leading to fixation of alternative venom phenotypes on a fine geographic scale, and are inconsistent with balancing selection to maintain both phenotypes within a single population. Our comparisons to biotic and abiotic factors further indicate that venom phenotype correlates with fang morphology and climatic variables. We hypothesize that links to fang morphology may be indicative of co-evolution of venom and other trophic adaptations, and that climatic variables may be linked to prey distributions and/or physiology, which in turn impose selection pressures on snake venoms.
Databáze: MEDLINE
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