Detection of positive selection signatures in populations around the world is helping to uncover recent human evolutionary history as well as the genetic basis of diseases. Most human evolutionary genomic studies have been performed in European, African, and Asian populations. However, populations with Native American ancestry have been largely underrepresented. Here, we used a genome-wide local ancestry enrichment approach complemented with neutral simulations to identify postadmixture adaptations underwent by admixed Chileans through gene flow from Europeans into local Native Americans. The top significant hits (P = 2.4×10⁻⁷) are variants in a region on chromosome 12 comprising multiple regulatory elements. This region includes rs12821256, which regulates the expression of KITLG, a well-known gene involved in lighter hair and skin pigmentation in Europeans as well as in thermogenesis. Another variant from that region is associated with the long noncoding RNA RP11-13A1.1, which has been specifically involved in the innate immune response against infectious pathogens. Our results suggest that these genes were relevant for adaptation in Chileans following the Columbian exchange.

中文翻译：

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智利混合后选择的目标是涉及色素沉着，生热和针对病原体的免疫防御的单体型。

在世界各地的人群中检测到阳性选择特征有助于发现人类最近的进化史以及疾病的遗传基础。大多数人类进化基因组研究已在欧洲，非洲和亚洲人群中进行。但是，具有美洲原住民血统的人口在很大程度上没有得到足够的代表。在这里，我们使用了全基因组的局部祖先富集方法，并辅以中性模拟，以鉴定混合后的智利人通过从欧洲人流向当地美洲原住民的基因流而经历的混合后适应。最重要的命中（P ＝ 2.4×10 ^-7）是染色体12上包含多个调控元件的区域中的变体。该区域包括rs12821256，它调节KITLG的表达，KITLG是一种众所周知的基因，与欧洲人的头发和皮肤色素沉着以及生热有关。来自该区域的另一个变体与长的非编码RNA RP11-13A1.1有关，后者已专门参与针对传染性病原体的先天免疫应答。我们的结果表明，这些基因与哥伦比亚交换后在智利的适应有关。