By Liz Droge-Young on June 24, 2016
Popular theories of why our human ancestors gained and then lost dark skin over the course of evolution may be incorrect, according to a new paper by UC San Francisco authors, who suggest that heavily pigmented skin evolved because it forms a stronger barrier against a host of environmental challenges. Because deeply pigmented skin requires more energy to produce, they propose, our ancestors shed some of these pigments through natural selection as they moved north and needed less protection against these threats.
“Work in our lab has shown that darkly pigmented skin has far better function, including a better barrier to water loss, stronger cohesion, and better antimicrobial defense, and we began to ponder the possible evolutionary significance of that,” said Peter Elias, MD, professor of dermatology. Elias co-authored the new paper, published in the June 21, 2016 online issue of the American Journal of Physical Anthropology, with his wife and frequent research collaborator Mary L. Williams, MD, clinical professor of dermatology at UCSF.