Testing the Toxicofera: Comparative transcriptomics casts doubt on the single, early evolution of the reptile venom system
Testing the Toxicofera: Comparative transcriptomics casts doubt on the single, early evolution of the reptile venom system
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DOI：
10.1016/j.toxicon.2014.10.004
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发表时间：
2014-12-15
期刊：
影响因子：
2.8
通讯作者：
Mulley, John F.
中科院分区：
文献类型：
--
作者：
Hargreaves, Adam D.;Swain, Martin T.;Mulley, John F.
在一组不同的爬行动物的毒液和唾液腺中发现了明显保守的基因互补序列，这导致了Toxicofera假说的发展-爬行动物毒液系统的单一早期进化。然而，这一假设主要是基于相对小规模的EST为基础的研究，只有毒液或唾液腺和毒性作用已被分配给一些物种中的一些推定Toxicoferan毒素。我们着手研究这些建议的毒液毒素转录本的分布，以调查在何种程度上保守的基因互补可能反映在以前的采样工作的偏见。我们对五种爬行动物的毒液和唾液腺以及其他身体组织的定量转录组学分析，以及对其他物种的可用RNA-Seq数据集的使用，表明用于支持Toxicofera建立和扩展的大多数基因实际上在多个身体组织中表达，并且最有可能代表一般维护或“管家”基因。因此，整个Toxicofera的基因互补的明显保守反映了不完整的组织取样的假象。因此，我们得出结论，毒液在爬行动物中进化了多次。(C)2014爱思唯尔有限公司版权所有。
The identification of apparently conserved gene complements in the venom and salivary glands of a diverse set of reptiles led to the development of the Toxicofera hypothesis - the single, early evolution of the venom system in reptiles. However, this hypothesis is based largely on relatively small scale EST-based studies of only venom or salivary glands and toxic effects have been assigned to only some putative Toxicoferan toxins in some species. We set out to examine the distribution of these proposed venom toxin transcripts in order to investigate to what extent conservation of gene complements may reflect a bias in previous sampling efforts. Our quantitative transcriptomic analyses of venom and salivary glands and other body tissues in five species of reptile, together with the use of available RNA-Seq datasets for additional species, shows that the majority of genes used to support the establishment and expansion of the Toxicofera are in fact expressed in multiple body tissues and most likely represent general maintenance or "housekeeping" genes. The apparent conservation of gene complements across the Toxicofera therefore reflects an artefact of incomplete tissue sampling. We therefore conclude that venom has evolved multiple times in reptiles. (C) 2014 Elsevier Ltd. All rights reserved.