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

没有体毛的头皮毛发是人类独有的特征，其进化意义尚不清楚。该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，研究人类群体中头发形态的潜在遗传结构，并实验测试头皮头发作为太阳热量增益屏障的功能。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，并为法医和皮肤病学研究提供信息。为该项目收集的数据将增加研究中未充分研究群体的代表性。该项目将为STEM研究领域中代表性不足的群体的本科生提供宝贵的研究机会，并将为非种族范式下的人类生物多样性教学提供材料。人的头发形态在连续光谱上从直到紧卷曲变化；然而，遗传学、皮肤病学和法医学的研究包括一系列定性（如波浪、卷曲）和种族（如头发）的描述符。“高加索人的头发”，“非洲人的头发”)。通过开发一种量化头发形态的方法，并研究非洲裔美国人不同群体的遗传变异，本研究利用遗传混合作为阐明人类群体中头发形态的基因型的手段。该项目的实验工作将验证人类头皮毛发形态在早期人类进化为防止太阳辐射热量增加的保护机制的假设。该项目还将对候选基因座（以前与头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存在选择，从而支持对人类头皮头发进化的热调节解释。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.