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Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico
Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme i...
Autores principales: | , , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926154/ https://www.ncbi.nlm.nih.gov/pubmed/27322321 http://dx.doi.org/10.3390/toxins8060188 |
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author | Zancolli, Giulia Baker, Timothy G. Barlow, Axel Bradley, Rebecca K. Calvete, Juan J. Carter, Kimberley C. de Jager, Kaylah Owens, John Benjamin Price, Jenny Forrester Sanz, Libia Scholes-Higham, Amy Shier, Liam Wood, Liam Wüster, Catharine E. Wüster, Wolfgang |
author_facet | Zancolli, Giulia Baker, Timothy G. Barlow, Axel Bradley, Rebecca K. Calvete, Juan J. Carter, Kimberley C. de Jager, Kaylah Owens, John Benjamin Price, Jenny Forrester Sanz, Libia Scholes-Higham, Amy Shier, Liam Wood, Liam Wüster, Catharine E. Wüster, Wolfgang |
author_sort | Zancolli, Giulia |
collection | PubMed |
description | Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A(2) such as Mojave toxin (MTX). Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species. |
format | Online Article Text |
id | pubmed-4926154 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-49261542016-07-06 Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico Zancolli, Giulia Baker, Timothy G. Barlow, Axel Bradley, Rebecca K. Calvete, Juan J. Carter, Kimberley C. de Jager, Kaylah Owens, John Benjamin Price, Jenny Forrester Sanz, Libia Scholes-Higham, Amy Shier, Liam Wood, Liam Wüster, Catharine E. Wüster, Wolfgang Toxins (Basel) Article Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A(2) such as Mojave toxin (MTX). Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species. MDPI 2016-06-16 /pmc/articles/PMC4926154/ /pubmed/27322321 http://dx.doi.org/10.3390/toxins8060188 Text en © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Zancolli, Giulia Baker, Timothy G. Barlow, Axel Bradley, Rebecca K. Calvete, Juan J. Carter, Kimberley C. de Jager, Kaylah Owens, John Benjamin Price, Jenny Forrester Sanz, Libia Scholes-Higham, Amy Shier, Liam Wood, Liam Wüster, Catharine E. Wüster, Wolfgang Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title | Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title_full | Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title_fullStr | Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title_full_unstemmed | Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title_short | Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico |
title_sort | is hybridization a source of adaptive venom variation in rattlesnakes? a test, using a crotalus scutulatus × viridis hybrid zone in southwestern new mexico |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4926154/ https://www.ncbi.nlm.nih.gov/pubmed/27322321 http://dx.doi.org/10.3390/toxins8060188 |
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