The rare characteristic of mammals that humans, elephants and whales share is their lack of hair. Each species’ common ancestors are significantly hairier, which could indicate that hairlessness has evolved independently. Researchers from the University of Pittsburgh, and the University of Utah, scanned multiple mammalian genomes to identify regions in the genomes that may have developed at an evolutionary speed or slow rate. Researchers from the University of Pittsburgh and Utah identified both protein-coding and noncoding genes that could explain hairlessness’ evolution in mammals.
This is a Neanderthal male. Image credit: Mauro Cutrona.
The hair is an important mammalian feature. It serves a multitude of purposes, including sensory perception and heat retention.
Many mammals lost their hair after losing much of it, despite the fact that the mammalian ancestral species may have had hair.
Numerous marine mammals including dolphins and whales as well as manatees and dugongs have sparse hair. This is likely due to their hydrodynamic adaptations that allow them to flourish in marine environments.
Larger terrestrial mammals like elephants and rhinoceroses have very little hair. This is likely because heat dissipation will be reduced by their large size.
Humans are not only relatively hairless but also have a long history of mystery.
Senior author, Dr. Nathan Clark (University of Pittsburgh), said that “we have used biological diversity to discover about our genetics.”
This is helping us pinpoint the regions in our genome which contribute to an important goal.”
Dr. Clark worked with his team to identify genes that were more rapidly evolving in hairless mammals than those found in hairy ones in order to unravel the mysteries of mammalian hair loss.
Clark stated that “Animals are being forced to shed their hair because of evolutionary pressure,” Clark explained.
They speed up genetic change that is allowed by natural selection.
Hair loss could be caused by genetic mutations. Other collateral damages could occur after the hair stops growing.
The authors devised computational algorithms that allowed them to compare multiple regions of the genome simultaneously.
The researchers mapped 19,149 genes as well as 343,598 regulatory areas across the many mammalian species that they analyzed.
They also took measures to eliminate genetic regions that could have been responsible for other traits specific to a species, like adapting to water life.
Clark stated that Dr. Clark was able to prove that his approach works by identifying known hair gene genes through an unbiased screening.
It also indicates that genes that were less clearly defined may be equally important to having hair or not.
This team now uses the same method to identify genetic regions that are involved in cancer prevention, life extension, and other medical conditions.
Clark stated, “This is an opportunity to identify global genetic mechanisms that underlie different characteristics.”
These findings were published by the journal eLife.
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Amanda Kowalczyk The authors and others. Mammalian hairlessness is based on a combination of noncoding and coding evolution. eLifePublished online on November 7, 2022. doi: 10.7554/eLife.76911