Although humans are somewhat of a hairy species, we aren’t saturated in body hair like some mammals because the genes responsible for human body hair growth have largely been disabled.

That’s according to researchers at University of Utah Health and the University of Pittsburgh who hope this finding can eventually lead to new ways to recover hair lost from chemotherapy treatment, balding and other diseases, such as alopecia.

The study points to a set of genes and regulatory regions of the genome that appear to be important for making hair. It shows that nature has set up the same strategy at least nine times in mammals of different evolutionary trees — the ancestors of dolphins, rhinos, naked mole rats and other hairless animals traveled along the same path to disable a common set of genes in order to shed their hair and fur.

“We have taken the creative approach of using biological diversity to learn about our own genetics,” Nathan Clark, a human geneticist at U of U Health, said in a press release. “This is helping us to pinpoint regions of our genome that contribute to something important to us.”

To unravel the mystery of hair loss in mammals, Clark, along with University of Pittsburgh researchers Amanda Kowalczyk and Maria Chikina, looked for genes in hairless animals that evolved at quicker rates than in hairy animals.

“As animals are under evolutionary pressure to lose hair, the genes encoding hair become less important,” Clark said. “That’s why they speed up the rate of genetic changes that are permitted by natural selection. Some genetic changes might be responsible for loss of hair. Others could be collateral damage after hair stops growing.”

The researchers also found the benefits of having a receding hairline. For instance, without dense hair, elephants are able to cool off more easily in hot climates and walruses are able to glide effortlessly in the water.

Kowalczyk found these and other hairless mammals have accumulated mutations in many of the same genes that code for keratin and additional elements that build the hair shaft and encourage growth.

“There are a good number of genes where we don’t know much about them,” she said, “We think they could have roles in hair growth and maintenance.”

Researchers hope to find more answers to hairlessness that may help lead to new ways of recovering hair after chemotherapy, balding or having a disorder such as alopecia. In the meantime, they are using the same method to analyze genes responsible for cancer and extended life.

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