Humans have a uniquely high density of sweat glands embedded in their skin — 10 times the density of chimpanzees and macaques.
[Scientists at Penn Medicine and the National Science Foundation] showed that the higher density of sweat glands in humans is due, to a great extent, to accumulated changes in a regulatory region of DNA that drives the expression of a sweat-gland-building gene. The discovery explains why humans are the sweatiest of the Great Apes.
“This is one of the clearest examples I’ve seen of pinpointing the genetic basis for one of the most distinctively human evolutionary traits,” said the study’s senior author, Yana Kamberov.
Scientists assume that humans’ high density of sweat glands reflects an ancient evolutionary adaptation. That adaptation, coupled with the loss of fur in early hominins (which promoted cooling through sweat evaporation), is thought to have made it easier to run, hunt and otherwise survive on the hot and relatively treeless African savanna.
While the study is mainly a result of fundamental biology research that shines a light on human evolution, it also should have long-term medical relevance, Kamberov said. “Severe wounds or burns often destroy sweat glands in skin, and so far we don’t know how to regenerate them u2014 but this study brings us closer to discovering how to do that.”