Intraspecific sequence and gene expression variation contribute little to venom diversity in sidewinder rattlesnakes ( Crotalus cerastes )
Intraspecific sequence and gene expression variation contribute little to venom diversity in sidewinder rattlesnakes ( Crotalus cerastes )
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种内序列和基因表达变异对响尾蛇（Crotalus cerastes）毒液多样性影响不大
DOI：
10.1098/rspb.2019.0810
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Parkinson, Christopher L.
中科院分区：
文献类型：
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作者：
Rautsaw, Rhett M.;Hofmann, Erich P.;Margres, Mark J.;Holding, Matthew L.;Strickland, Jason L.;Mason, Andrew J.;Rokyta, Darin R.;Parkinson, Christopher L.
性状可以通过基因表达或蛋白质编码序列的变化迅速进化。然而，这些形式的遗传变异可以相互关联，其中一种的变化可以影响另一种。因此，我们可能预计缺乏差异表达的性状会优先通过蛋白质序列的变化或形态适应而进化。由于缺乏差异表达的分布响尾蛇（Crotalus cerastes），我们测试了这一假设，通过比较的编码区的基因表达的毒腺转录组和牙形态。我们计算了Tajima在四个群体中的DandFST，比较了毒素和非毒素位点。总的来说，我们发现很少有证据表明种群之间的定向选择或分化，这表明蛋白质序列的变化并不构成响尾蛇毒液进化的基础，也不表明毒素处于极端的变异选择压力之下。虽然低表达毒素在种群之间没有更高的序列差异，但它们确实具有更多的选择可以作用的常设变异。此外，我们发现，在人口之间的尖牙长度显着差异。缺乏差异表达和序列分歧表明sidewinders-鉴于他们的通才饮食，适度的基因流和环境变化-是稳定的选择功能，以保持一个通才表型。总的来说，我们证明了研究基因表达和蛋白质编码变化之间的关系，以了解复杂性状的进化的重要性。
Traits can evolve rapidly through changes in gene expression or protein-coding sequences. However, these forms of genetic variation can be correlated and changes to one can influence the other. As a result, we might expect traits lacking differential expression to preferentially evolve through changes in protein sequences or morphological adaptation. Given the lack of differential expression across the distribution of sidewinder rattlesnakes (Crotalus cerastes), we tested this hypothesis by comparing the coding regions of genes expressed in the venom gland transcriptomes and fang morphology. We calculated Tajima'sDandFSTacross four populations comparing toxin and nontoxin loci. Overall, we found little evidence of directional selection or differentiation between populations, suggesting that changes to protein sequences do not underlie the evolution of sidewinder venom or that toxins are under extremely variant selection pressures. Although low-expression toxins do not have higher sequence divergence between populations, they do have more standing variation on which selection can act. Additionally, we found significant differences in fang length among populations. The lack of differential expression and sequence divergence suggests sidewinders—given their generalist diet, moderate gene flow and environmental variation—are under stabilizing selection which functions to maintain a generalist phenotype. Overall, we demonstrate the importance of examining the relationship between gene expression and protein-coding changes to understand the evolution of complex traits.