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

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.