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The end-goal of my research is to better understand human hair diversity and answer the question: ‘Why did modern variation in human scalp hair evolve?’
To answer that question, I am focusing on:
- Figuring out how best to measure and describe hair curl and color
- Studying genetic variation relevant to hair
- Testing the potential for evolutionary advantages to various hair traits
Measuring and describing hair curl and color
Most of the work I’ve done so far has been focused on finding the best way to understand differences in hair phenotype (its appearance). We can, of course, describe hair categorically as ‘blond’, ‘red’, ‘wavy’ or ‘straight’.
But in reality, there is no clear dividing line between e.g. ‘Dark blond’ and ‘light brown’ or ‘very wavy’ and ‘slightly curly’ because these traits exist on a continuous spectrum.
So I am measuring things like the radius of curls and amount of melanin in hair, among other things, to develop good methods to quantify hair curl and color.
The genetics of hair
A well-described phenotype (observable trait) can help us find the genotypes for hair traits. Linking certain hair traits to specific mutations in genes is interesting in its own right, but it could also help us figure out when these hair traits evolved and see which populations have the genetic markers for them.
One way of finding out the genes that play a role in hair variation is to collect large samples of hair and correlate phenotypes to genotypes.
However, studying the genes that are expressed during the development and growth of the hair follicle can help give us clues as to where to look for mutations responsible for particular hair variants. Though I am not personally involved in developmental work, it is something I am studying through existing literature.
Hair traits as evolutionary adaptations
Answering any evolutionary questions will involve using the phenotypic and genetic information that is collected to test specific hypotheses. I’m especially interested in doing research on tightly curled African hair and seeing whether it could have evolved as a thermoregulatory adaptation (for keeping our heads cool) as has been suggested before.
In addition to this, I’d like to find out whether, once humans migrated out of Africa, differences in hair texture and color could have been adaptations to environmental pressures or whether they were “random”, neutral byproducts of populations evolving in isolation.