Research Begins to Explore What Makes EDAR Gene Advantageous

According to a recent study by a team of Harvard researchers from across the University, specialists in thermoregulation, dermatologists, and hair experts have one thing in common: the EDAR gene.

Using a tool she has developed over the past several years, Pardis C. Sabeti, one of the lead researchers of the study and an associate professor of organismic and evolutionary biology, was able to identify EDAR as an evolutionary advantageous gene. With this study Sabeti and her co-workers sought to understand what makes the gene so advantageous.

To clearly identify its effects on physical traits, Yana G. Kamberov, a research fellow in genetics at Harvard Medical School, isolated and implanted the single gene into laboratory mice. The resulting mice exhibited not only thicker hair and altered teeth shape but also an unexpected increase in sweat glands and diminished mammary gland sizes.

EDAR’s importance to sweat glands was further confirmed by analyzing the genomes of living humans of Han Chinese descent. Those with a similarly high frequency of sweat glands also possessed EDAR.

The ability to sweat bears great evolutionary significance as it is one of the characteristics that distinguishes humans from other animals. Now that the researchers have established causality between the EDAR gene and its many physical manifestations, they can begin to investigate whether sweating­—or one of the other many traits expressed by the gene—makes it evolutionarily favored.

The gene’s many roles have brought together a diverse range of specialists to collaborate on this project. From specialists in thermoregulation—how the body maintains its optimum temperature—to dermatologists to hair experts, each scientist offers a unique perspective on “why we are the way we are,” Sabeti said.

“Because I work on hair, I spend a lot of time talking to cosmetic companies,” said Bruce A. Morgan, an associate professor of dermatology at Harvard Medical School. “When this gene first came out—a gene that will make your hair thicker—all the cosmetic companies thought, ‘Oh, there’s the secret to life.’”

Eventually, Sabeti hopes to apply her gene-identifying technology to epidemiology in an attempt to correlate certain genes with increased odds of immunity or disease-resistance. She has located over 400 candidates for evolutionarily favored genes that will potentially shed light on ways to prevent or treat illnesses.

“Anything that’s been critical for our survival in the past may unlock mysteries of how to keep human survival going forward,” Sabeti said.

—Staff writer Jessica A. Barzilay can be reached at jessicabarzilay@college.harvard.edu. Follow her on Twitter @jessicabarzilay.