The Fur Gambit

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Humans, dolphins and elephants all lack fur – unlike other mammals.

Humans used to have a lot of fur but lost it due to evolutionary pressures, including thermoregulation and the reduction of parasites.

A new genetic study, however, found that hairless mammals, including humans, still have those fur genes – but they have been “switched off,” according to Science Alert.

Scientists conducted an extensive study through nearly 20,000 coding genes and 350,000 regulatory ones across more than 60 different mammal species.

They explained that hairlessness evolved independently at least nine different times along different branches of the mammalian family tree. The selection pressures leading to hair loss also vary among different species: For example, marine mammals such as dolphins lost them to become sleeker while moving in water.

The team also discovered that genetic changes in furless species were usually caused by mutations in the same sets of genes, such as those related to the structure of the hair itself.

They noted that humans still have these fur-coding genes, but they have been set to “off” through the accumulation of these mutations.

Even so, their analysis found hundreds of new hair-related regulatory genes and potential new hair-coding genes, which can become important for people trying to recover lost hair due to disorders or chemotherapy.

“There are a good number of genes (that) … we don’t know much about,” said lead author Amanda Kowalczyk. “We think they could have roles in hair growth and maintenance.”