Positive selection on nucleotide substitutions and indels in accessory gland proteins of the Drosophila pseudoobscura subgroup
Positive selection on nucleotide substitutions and indels in accessory gland proteins of the Drosophila pseudoobscura subgroup
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DOI：
10.1007/s00239-005-0239-4
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发表时间：
2006-06-01
影响因子：
3.9
通讯作者：
Hellberg, Michael E.
中科院分区：
文献类型：
--
作者：
Schully, Sheri Dixon;Hellberg, Michael E.
由于核苷酸取代的正向选择，编码生殖蛋白的基因经常迅速分化。虽然这种一般模式已得到很好的确立，但特定生殖基因在不同进化枝中经历相似选择的程度却很少被探索，除了核苷酸取代（例如插入缺失）之外，正选择的可能目标也没有受到太多关注。在这里，我们检查了编码五种辅助腺蛋白 (Acps)（Acp26Aa、Acp32CD、Acp53Ea、Acp62F 和 Acp70A）的基因的正选择特征，这些基因最初是从黑腹果蝇中描述的，但在 D.pseudoobscura 亚组中具有可识别的直系同源物。我们比较了 D. psuedoobscura 亚群和 D. melanogaster 亚群中的选择模式。在两个亚组的 Acp26Aa 和 Acp62F 中发现了类似的正选择模式，而 Acp53Ea 和 Acp70A 在两个亚组中都经历了纯化选择。因此，这些蛋白质在很长一段时间（> 21-MY）内仍然是类似类型选择的目标。我们还在 Acp26Aa 和 Acp32CD 中发现了一些插入缺失替换和多态性。这些插入缺失发生在与 D.pseudoobscura 亚组中 Acp26Aa 的正选择核苷酸取代相同的区域，但不在黑腹果蝇亚组中。 D.pseudoobscura 亚群中 Acp26Aa 内的插入/缺失替换率高达果蝇基因组非编码区域的几倍。这表明 indel 取代可能处于正选择之下，并且可能在某些 Acps 的分化中发挥关键作用。
Genes encoding reproductive proteins often diverge rapidly due to positive selection on nucleotide substitutions. While this general pattern is well established, the extent to which specific reproductive genes experience similar selection in different clades has been little explored, nor have possible targets of positive selection other than nucleotide substitutions, such as indels, received much attention. Here, we inspect for the signature of positive selection in the genes encoding five accessory gland proteins (Acps) (Acp26Aa, Acp32CD, Acp53Ea, Acp62F, and Acp70A) originally described from Drosophila melanogaster but with recognizable orthologues in the D. pseudoobscura subgroup. We compare patterns of selection within the D. psuedoobscura subgroup to those in the D. melanogaster subgroup. Similar patterns of positive selection were found in Acp26Aa and Acp62F in the two subgroups, while Acp53Ea and Acp70A experienced purifying selection in both subgroups. These proteins have thus remained targets for similar types of selection over long (> 21-MY) periods of time. We also found several indel substitutions and polymorphisms in Acp26Aa and Acp32CD. These indels occur in the same regions as positively selected nucleotide substitutions for Acp26Aa in the D. pseudoobscura subgroup but not in the D. melanogaster subgroup. Rates of indel substitution within Acp26Aa in the D. pseudoobscura subgroup were up to several times those in noncoding regions of the Drosophila genome. This suggests that indel substitutions may be under positive selection and may play a key role in the divergence of some Acps.