Harvard researchers are using scientific tools more often deployed to probe major health problems to understand the recent evolution of humans. In a study published Thursday, scientists used DNA blueprints from living people and experiments in laboratory mice to gain insight into a genetic change that became common among East Asians some 30,000 years ago.
They showed that the particular gene variant causes the development of more sweat glands and speculated it could have given people a survival advantage in the humid climate of the region.
Thus far, most of the work in this field had more to do with finding the genetic underpinnings of traits scientists already understood, such as the spread of the gene that allows human beings to continue to digest milk in adulthood. This time, they wanted to use the genes as a clue to understand what traits were adaptive during human evolution.
To help unravel the story, a large interdisciplinary team used genetic manipulation to create laboratory mice with the same version of the human gene. In the study appearing in the journal Cell, they reported the particular mutation that is prevalent among East Asians caused the mice to have thicker hair and more sweat glands on their footpads and changed the structure of their mammary glands.
The sweat gland finding was especially interesting. Sweat, it turns out, is one of the traits that sets people apart from other animals. Even closely-related chimpanzees can sweat through only a limited number of body areas, such as their hands or nose. Humans’ ability to sweat has helped make them so good at running long distances — which was important for hunter-gatherers.
“It gives you a history of what traits were critical for survival in humans,” said Pardis Sabeti, associate professor of systems biology at Harvard University and a member of the Broad Institute, a Cambridge genomics research center.