Genomic signatures of local adaptation in the Drosophila immune response
Genomic signatures of local adaptation in the Drosophila immune response
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DOI：
10.1080/19336934.2017.1337612
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发表时间：
2017-01-01
期刊：
影响因子：
1.2
通讯作者：
Clark, Andrew G.
中科院分区：
文献类型：
--
作者：
Early, Angela M.;Clark, Andrew G.
随着环境和病原体景观的变化，宿主防御必须进化以保持有效。由于这种选择压力，对基因序列数据的物种间比较经常发现免疫基因是整个基因组中进化最快的基因之一。然而，这些免疫适应的完整程度和性质在很大程度上仍未被探索。在最近的一项研究中，我们分析了黑腹果蝇免疫途径不同组成部分的选择模式。虽然我们在一些免疫过程中发现了正选择的证据，但免疫基因并不普遍具有强选择的特征。相反，我们甚至发现一些免疫函数表现出比预期更大的约束。总的来说，这些结果突出了两个主要因素，它们似乎在决定基因的进化速度方面发挥了巨大作用：基因靶向的病原体类型和基因在免疫网络中的位置。这些结果加入了越来越多的文献，强调免疫适应的复杂性。不是所有免疫基因都有统一的强选择，而是病原体特异性和宿主遗传约束的组合似乎在确定每个免疫基因的个体进化轨迹中发挥关键作用。
As environments and pathogen landscapes shift, host defenses must evolve to remain effective. Due to this selection pressure, among-species comparisons of genetic sequence data often find immune genes to be among the fastest evolving genes across the genome. The full extent and nature of these immune adaptations, however, remain largely unexplored. In a recent study, we analyzed patterns of selection within distinct components of the Drosophila melanogaster immune pathway. While we found evidence of positive selection within some immune processes, immune genes were not universally characterized by signatures of strong selection. On the contrary, we even found that some immune functions show greater than expected constraint. Overall these results highlight 2 major factors that appear to play an outsize role in determining a gene's evolutionary rate: the type of pathogen the gene targets and the gene's position within the immune network. These results join a growing body of literature that highlight the complexity of immune adaptation. Rather than there being uniformly strong selection across all immune genes, a combination of pathogen-specificity and host genetic constraints appear to play key roles in determining each immune gene's individual evolutionary trajectory.