The FADS locus contains the genes FADS1 and FADS2 that encode enzymes involved in the synthesis of long-chain polyunsaturated fatty acids. This locus appears to have been a repeated target of selection in human evolution, likely because dietary input of long-chain polyunsaturated fatty acids varied over time depending on environment and subsistence strategy. Several recent studies have identified selection at the FADS locus in Native American populations, interpreted as evidence for adaptation during or subsequent to the passage through Beringia. Here, we show that these signals are confounded by independent selection—postdating the split from Native Americans—in the European and, possibly, the East Asian populations used in the population branch statistic test. This is supported by direct evidence from ancient DNA that one of the putatively selected haplotypes was already common in Northern Eurasia at the time of the separation of Native American ancestors. An explanation for the present-day distribution of the haplotype that is more consistent with the data is that Native Americans retain the ancestral state of Paleolithic Eurasians. Another haplotype at the locus may reflect a secondary selection signal, although its functional impact is unknown.

中文翻译：

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在美国原住民人群中，在FADS所在地进行选择的证据有限。

的FADS基因座含有的基因FADS1和FADS2，参与长链的合成编码酶的多不饱和脂肪酸。该场所似乎已成为人类进化过程中反复选择的目标，这可能是由于长链多不饱和脂肪酸的饮食输入随时间而变化，具体取决于环境和生存策略。最近的一些研究已经确定了FADS的选择原住民群体中的基因座，被解释为通过白令菌期间或之后适应的证据。在这里，我们表明，在人口分支统计检验中使用的欧洲乃至东亚人口中，这些信号是由独立选择（在与美洲原住民的分裂之后）所混淆的。古代DNA的直接证据支持了这一点，即在美洲原住民祖先分离时，一种推定的单倍型在北欧亚大陆已经很普遍。当前单倍型分布与数据更一致的一种解释是，美洲原住民保留了旧石器时代的欧亚大陆的祖先状态。尽管其功能影响尚不清楚，但该位点的另一种单倍型可能反映了次级选择信号。