Anatomically modern humans started to exit Africa for the first time at least 60,000 years ago (ya). Along their journey across the globe, they encountered and admixed with other hominins that are now extinct, such as the Neanderthals or Denisovans. Given the deep divergence time between ancient hominins and modern humans, such admixture events left molecular traces in nonAfrican populations that are still visible today in their genomes [1]. Over the past few years, there is accumulating evidence to suggest that these segments of “archaic” DNA have the potential to contribute to phenotypic differences between contemporary individuals and populations [2]. Yet, to understand the genuine contribution of archaic alleles to the genetic architecture of complex traits, it is necessary to account for the diverse selective pressures that have acted upon introgressed alleles. Here, we discuss recent findings on how natural selection—either negative or positive—has shaped the landscape of Neanderthal ancestry in the genomes of modern Eurasians, and comment on the contribution of archaic haplotypes to present-day phenotypic variation.

中文翻译：

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古老基因渗入的功能后果及其对健康的影响

从解剖学上讲，现代人类至少在 60,000 年前第一次开始离开非洲（ya）。在他们穿越全球的旅程中，他们遇到并混入了其他现已灭绝的人类，例如尼安德特人或丹尼索瓦人。鉴于古代人类与现代人类之间存在巨大的分歧，这种混合事件在非非洲人群中留下了分子痕迹，这些痕迹今天在他们的基因组中仍然可见[1]。在过去几年中，越来越多的证据表明这些“古老”DNA 片段有可能导致当代个体和人群之间的表型差异 [2]。然而，要了解古老等位基因对复杂性状遗传结构的真正贡献，有必要说明作用于渗入等位基因的不同选择压力。在这里，我们讨论了最近关于自然选择（无论是消极还是积极）如何塑造了现代欧亚人基因组中尼安德特人血统的景观的最新发现，并评论了古代单倍型对当今表型变异的贡献。