Effect of Archaic Admixture on Modern Human Adaptations

最近的遗传学研究表明，现代人在过去与古人类物种如尼安德特人和丹尼索瓦人杂交。在现代人类中发现的一些古老基因似乎在免疫和皮肤和毛发的适应中发挥着重要作用，但我们对古老基因的贡献和影响的理解仍然不完整。该项目将研究来自古代杂交的DNA对现代人类的影响，告诉我们现代人类中有多少古老的DNA，以及这些DNA如何影响身体脂肪。研究者将开发并免费提供用于研究杂交和适应性进化的统计工具。这些工具将解决目前限制我们对人类古老基因理解的分析偏见，并将在其他研究领域（如保护生物学）中发挥作用，因为这些领域需要定义和区分物种。该项目将支持培训一名人类进化遗传学研究生，传播研究结果，作为关于进化的本科教科书的一部分，并通过经常向当地学校和社区团体举办关于人类进化的讲座，从幼儿园到12年级，向公众宣传。我们目前对古代混合物的理解受到普遍存在的统计偏差的影响。考虑到已知古老等位基因在几个遗传位点影响现代人类适应性表型，解决这些偏见是很重要的。为了纠正这个问题，本项目将开发一种新的统计方法，利用基因组数据估计多个种群之间的基因流。该方法将有可能估计现代人类群体中的古代DNA水平，祖先群体的大小和分离时间，以及古代DNA对身高，血压或体重等多基因特征的影响。该项目将把这种方法应用于现代人类脂肪储存的研究，测试我们从尼安德特人那里继承了储存脂肪的倾向的假设-这是他们适应更新世欧洲季节性食物短缺的遗迹。

Recent genetic studies indicate that modern humans interbred with archaic hominin species such as Neanderthals and Denisovans in the past. Some of the archaic genes found in modern humans appear to play important roles in immunity and in adaptations involving skin and hair, but our understanding of the contributions and effects of archaic genes is still incomplete. This project will study the effects on modern humans of DNA derived from ancient interbreeding, telling us how much archaic DNA is in modern humans and how this DNA affects body fat. The investigator will develop and make freely available statistical tools for the study of interbreeding and adaptive evolution. These tools will address current analytical biases that limit our understanding of archaic genes in humans, and will be useful in other fields of study, like conservation biology, where there is a need to define and distinguish among species. The project will support training of a graduate student in human evolutionary genetics, dissemination of findings as part of an undergraduate textbook on evolution, and K-12 and public outreach through frequent lectures on human evolution to local school and community groups. Our current understanding of archaic admixture is compromised by pervasive statistical biases. Given that archaic alleles are known to influence modern human adaptive phenotypes at several genetic loci, it is important that these biases be addressed. To correct this problem, this project will develop a new statistical method to estimate gene flow among multiple populations using genomic data. The method will make it possible to estimate levels of archaic DNA in modern human populations, sizes and separation times of ancestral populations, and effects of archaic DNA on polygenic characters such as stature, blood pressure, or body weight. The project will apply this method to a study of fat storage in modern humans, testing the hypothesis that we have inherited from Neanderthals a tendency to store fat - a relic of their adaptation to seasonal food shortages in Pleistocene Europe.