The Deep Origin and Recent Loss of Venom Toxin Genes in Rattlesnakes.
Curr Biol
; 26(18): 2434-2445, 2016 09 26.
Article
em En
| MEDLINE
| ID: mdl-27641771
ABSTRACT
The genetic origin of novel traits is a central but challenging puzzle in evolutionary biology. Among snakes, phospholipase A2 (PLA2)-related toxins have evolved in different lineages to function as potent neurotoxins, myotoxins, or hemotoxins. Here, we traced the genomic origin and evolution of PLA2 toxins by examining PLA2 gene number, organization, and expression in both neurotoxic and non-neurotoxic rattlesnakes. We found that even though most North American rattlesnakes do not produce neurotoxins, the genes of a specialized heterodimeric neurotoxin predate the origin of rattlesnakes and were present in their last common ancestor (â¼22 mya). The neurotoxin genes were then deleted independently in the lineages leading to the Western Diamondback (Crotalus atrox) and Eastern Diamondback (C. adamanteus) rattlesnakes (â¼6 mya), while a PLA2 myotoxin gene retained in C. atrox was deleted from the neurotoxic Mojave rattlesnake (C. scutulatus; â¼4 mya). The rapid evolution of PLA2 gene number appears to be due to transposon invasion that provided a template for non-allelic homologous recombination.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Crotalus
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Venenos de Crotalídeos
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Proteínas de Répteis
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Fosfolipases A2
Limite:
Animals
Idioma:
En
Revista:
Curr Biol
Ano de publicação:
2016
Tipo de documento:
Article