Effect of Archaic Admixture on Modern Human Adaptations

最近的遗传学研究表明，现代人在过去曾与尼安德特人和丹尼索瓦人等古人类物种杂交。在现代人类中发现的一些古老基因似乎在免疫和皮肤和头发的适应中发挥了重要作用，但我们对古代基因的贡献和影响的了解仍然不完整。这个项目将研究来自古代杂交的DNA对现代人的影响，告诉我们现代人中有多少古老的DNA，以及这种DNA如何影响身体脂肪。研究人员将开发并免费提供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理解人类古老基因的分析偏见，并将在其他研究领域有用，如保护生物学，在那里需要定义和区分物种。该项目将支持对一名研究生进行人类进化遗传学方面的培训，将研究结果作为本科生进化论教科书的一部分进行传播，并通过经常向当地学校和社区团体举办关于人类进化论的讲座，支持K-12和公共宣传。我们目前对古代混合体的理解受到普遍存在的统计偏差的影响。鉴于古老的等位基因已知在几个遗传位点上影响现代人的适应性表型，解决这些偏见是很重要的。为了纠正这个问题，该项目将开发一种新的统计方法，使用基因组数据来估计多个种群之间的基因流动。该方法将使估计现代人类种群中古代DNA的水平、祖先种群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成为可能。该项目将把这种方法应用于对现代人脂肪储存的研究，检验我们从尼安德特人那里遗传来的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.