Naranjo Santiago, Smith Justin D, Artieri Carlo G, Zhang Mian, Zhou Yiqi, Palmer Michael E, Fraser Hunter B
Department of Biology, Stanford University, Stanford, California, United States of America.
Department of Genetics, Stanford University, Stanford, California, United States of America.
PLoS Genet. 2015 Dec 29;11(12):e1005751. doi: 10.1371/journal.pgen.1005751. eCollection 2015 Dec.
Although single genes underlying several evolutionary adaptations have been identified, the genetic basis of complex, polygenic adaptations has been far more challenging to pinpoint. Here we report that the budding yeast Saccharomyces paradoxus has recently evolved resistance to citrinin, a naturally occurring mycotoxin. Applying a genome-wide test for selection on cis-regulation, we identified five genes involved in the citrinin response that are constitutively up-regulated in S. paradoxus. Four of these genes are necessary for resistance, and are also sufficient to increase the resistance of a sensitive strain when over-expressed. Moreover, cis-regulatory divergence in the promoters of these genes contributes to resistance, while exacting a cost in the absence of citrinin. Our results demonstrate how the subtle effects of individual regulatory elements can be combined, via natural selection, into a complex adaptation. Our approach can be applied to dissect the genetic basis of polygenic adaptations in a wide range of species.
尽管已经确定了几种进化适应背后的单个基因，但复杂的多基因适应的遗传基础却极难精确查明。在此，我们报告称，芽殖酵母奇异酵母最近进化出了对桔霉素（一种天然存在的霉菌毒素）的抗性。通过应用全基因组顺式调控选择测试，我们鉴定出了五个参与桔霉素反应的基因，这些基因在奇异酵母中持续上调。其中四个基因是抗性所必需的，并且在过表达时也足以增加敏感菌株的抗性。此外，这些基因启动子中的顺式调控差异有助于产生抗性，同时在没有桔霉素的情况下会付出代价。我们的结果表明，单个调控元件的微妙效应是如何通过自然选择组合成一种复杂适应的。我们的方法可用于剖析广泛物种中多基因适应的遗传基础。
