Doctoral Dissertation Research: Investigating the genetic architecture and adaptive characteristics of human hair

没有体毛的头皮是人类独有的特征，其进化意义还没有被很好地理解。这一博士论文项目将开发一种用于定量测量头发纤维形态的数字工具，调查人类群体头发形态的潜在遗传结构，并通过实验测试头皮头发作为太阳热获取屏障的功能。作为该项目的一部分开发的方法将促进我们对人类适应特征的理解，并为法医和皮肤病研究提供信息。为该项目收集的数据将增加研究不足群体在研究中的代表性。这个项目将为STEM研究领域中代表性不足的本科生提供宝贵的研究机会，并将生成非种族范式下关于人类生物多样性的教学材料。人类头发的形态连续变化，从直到紧密卷曲；然而，遗传学、皮肤病和法医学的研究包括一系列描述符，这些描述符可以是定性的(例如卷曲的、卷曲的)和种族的(例如：“高加索头发”、“非洲类型的头发”)。通过开发一种量化头发形态的方法并研究不同的非裔美国人群体中的遗传变异，这项研究利用遗传混合作为一种手段来阐明人类群体头发形态的基因类型。这个项目中的实验工作将检验这样一个假设，即人类早期头皮毛发形态是作为一种保护机制来抵御太阳辐射的热量获得的。该项目还将对候选基因(以前与毛发形态或毛囊发育相关)进行一系列选择测试，以测试是否有证据表明头发相关基因的选择可以支持对人类头皮毛发进化的体温调节解释。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Scalp hair in the absence of body hair is a uniquely human trait, whose evolutionary significance is not well understood. This doctoral dissertation project will develop a digital tool for the quantitative measurement of hair fiber morphology, to investigate the underlying genetic architecture of hair morphology across human groups, and experimentally test the function of scalp hair as a barrier to solar heat gain. The methods developed as part of this project will advance our understanding of human adaptive traits and also inform forensic and dermatological research. Data collected for this project will increase the representation of understudied groups in research. This project will provide valuable research opportunities for undergraduates from groups underrepresented in STEM research fields and will generate materials for teaching about human biological diversity in a non-racial paradigm.Human hair morphology varies on a continuous spectrum from straight to tightly curled; however, research in genetics, dermatology, and forensics incudes a range of descriptors that can be qualitative (e.g. wavy, frizzy) and racial (e.g. 'Caucasian hair,' 'African-type hair'). By developing a method to quantify hair morphology and studying the genetic variation in a diverse group of African Americans, this study leverages genetic admixture as a means of elucidating genotypes underlying hair morphology across human groups. The experimental work in this project will test the hypothesis that human scalp hair morphology evolved in early Homo as a protective mechanism against heat gain from solar radiation. This project will additionally carry out a series of tests of selection on candidate loci (previously associated with hair morphology or hair follicle development) to test whether there is evidence of selection in hair-related genes that would support a thermoregulatory explanation for the evolution of human scalp hair.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.