Restriction and recruitment-gene duplication and the origin and evolution of snake venom toxins.
Restriction and recruitment-gene duplication and the origin and evolution of snake venom toxins.
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DOI：
10.1093/gbe/evu166
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发表时间：
2014-08
影响因子：
3.3
通讯作者：
Mulley JF
中科院分区：
文献类型：
--
作者：
Hargreaves AD;Swain MT;Hegarty MJ;Logan DW;Mulley JF
蛇毒被假设是通过一个过程起源和多样化的，该过程涉及编码身体蛋白质的基因的复制，随后将拷贝募集到毒液腺，在那里自然选择发挥作用以发展或增加毒性。然而，基因复制是已知的脊椎动物基因组中是一种罕见的事件，重复的基因的招聘到一个新的表达域（新功能化）是一个更罕见的过程，需要在上游调控区的转录因子结合位点的新组合的演变。因此，虽然这种关于蛇毒进化的假设是非常不可能的，应该谨慎对待，但它仍然经常被认为是既定的事实，阻碍了对蛇毒毒素真正起源的研究。为了严格评估这一假设，我们已经产生了五种有毒和无毒爬行动物的身体组织和唾液腺和毒腺的转录组数据。我们对这些数据的比较转录组学分析表明，蛇毒并没有通过复制和招募编码身体蛋白的基因的假设过程而进化。事实上，我们的研究结果表明，许多拟议的毒液毒素实际上是在各种各样的身体组织中表达的，包括无毒爬行动物的唾液腺，因此这些基因在复制后仅限于毒液腺，而不是招募。因此，蛇毒是通过复制和亚功能化编码现有唾液蛋白的基因而进化的。这些结果突出了进化生物学中优雅而直观的“如此故事”的危险。
Snake venom has been hypothesized to have originated and diversified through a process that involves duplication of genes encoding body proteins with subsequent recruitment of the copy to the venom gland, where natural selection acts to develop or increase toxicity. However, gene duplication is known to be a rare event in vertebrate genomes, and the recruitment of duplicated genes to a novel expression domain (neofunctionalization) is an even rarer process that requires the evolution of novel combinations of transcription factor binding sites in upstream regulatory regions. Therefore, although this hypothesis concerning the evolution of snake venom is very unlikely and should be regarded with caution, it is nonetheless often assumed to be established fact, hindering research into the true origins of snake venom toxins. To critically evaluate this hypothesis, we have generated transcriptomic data for body tissues and salivary and venom glands from five species of venomous and nonvenomous reptiles. Our comparative transcriptomic analysis of these data reveals that snake venom does not evolve through the hypothesized process of duplication and recruitment of genes encoding body proteins. Indeed, our results show that many proposed venom toxins are in fact expressed in a wide variety of body tissues, including the salivary gland of nonvenomous reptiles and that these genes have therefore been restricted to the venom gland following duplication, not recruited. Thus, snake venom evolves through the duplication and subfunctionalization of genes encoding existing salivary proteins. These results highlight the danger of the elegant and intuitive “just-so story” in evolutionary biology.
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影响因子：
2.8
作者：
Fry, Bryan G.;Scheib, Holger;Casewell, Nicholas R.
通讯作者：
Casewell, Nicholas R.
影响因子：
2.8
作者：
Fry, Bryan G.;Casewell, Nicholas R.;Jackson, Timothy N. W.
通讯作者：
Jackson, Timothy N. W.
DOI：
10.1098/rspb.2004.2969
发表时间：
2005-02-07
影响因子：
4.7
作者：
Cotton, JA;Page, RDM
通讯作者：
Page, RDM
影响因子：
3.3
作者：
Fahmi, Laila;Makran, Bouchra;Calvete, Juan J.
通讯作者：
Calvete, Juan J.
影响因子：
64.8
作者：
Fry, BG;Vidal, N;Kochva, E
通讯作者：
Kochva, E