Can humans still grow fur? New study discovers the genes

Can we 'turn on' genes for thick hair?

According to the study, humans appear to have the genes for a thick layer of body hair, but evolution has rendered them inactive. It also identifies several genes and genomic areas that appear to be crucial for the development of hair.

The study goes on to show that nature has at least nine times used specific methods for creating hair in mammals from different evolutionary branches. The researchers believe this insight may eventually lead to novel treatments for those who have hair loss issues or who have undergone chemotherapy or balding.

“We have taken the creative approach of using biological diversity to learn about our own genetics,” says Nathan Clark, Ph.D., a human geneticist at U of U Health. Clark carried out much of the research while at the University of Pittsburgh with Amanda Kowalczyk, Ph.D., and Maria Chikina, Ph.D. “This is helping us to pinpoint regions of our genome that contribute to something important to us,” they added.

Decoding the mystery of hair loss

Researchers looked for genes in hairless animals that developed more quickly than their counterparts in hairy animals in order to unravel the enigma of mammalian hair loss.

“As animals are under evolutionary pressure to lose hair, the genes encoding hair become less important,” Clark says.

“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.”

They created computer techniques that could compare hundreds of genomic areas simultaneously in order to carry out the search. They examined 343,598 regulatory areas and 19,149 genes that were shared by the various mammalian species under study. They also made precautions to ignore genomic areas that were involved in the evolution of other species-specific features, such as aquatic adaptations.

According to Clark, the method's success was shown by the fact that the unbiased screen discovered known hair genes. It also implies that the less well-defined genes found on the screen may have a similar role in determining whether or not a person has hair.

Clark and colleagues are currently defining genomic regions related to cancer prevention, extending longevity, and comprehending other medical diseases using the same methodology.

Study abstract:

Body hair is a defining mammalian characteristic, but several mammals, such as whales, naked mole rats, and humans, have notably less hair. To find the genetic basis of reduced hair quantity, we used our evolutionary-rates-based method, RERconverge, to identify coding and noncoding sequences that evolve at significantly different rates in so-called hairless mammals compared to hairy mammals. Using RERconverge, we performed a genome-wide scan over 62 mammal species using 19,149 genes and 343,598 conserved noncoding regions. In addition to detecting known and potential novel hair-related genes, we also discovered hundreds of putative hair-related regulatory elements. Computational investigation revealed that genes and their associated noncoding regions show different evolutionary patterns and influence different aspects of hair growth and development. Many genes under accelerated evolution are associated with the structure of the hair shaft itself, while evolutionary rate shifts in noncoding regions also included the dermal papilla and matrix regions of the hair follicle that contribute to hair growth and cycling. Genes that were top ranked for coding sequence acceleration included known hair and skin genes KRT2, KRT35, PKP1, and PTPRM that surprisingly showed no signals of evolutionary rate shifts in nearby noncoding regions. Conversely, accelerated noncoding regions are most strongly enriched near regulatory hair-related genes and microRNAs, such as mir205, ELF3, and FOXC1, that themselves do not show rate shifts in their protein-coding sequences. Such dichotomy highlights the interplay between the evolution of protein sequence and regulatory sequence to contribute to the emergence of a convergent phenotype.