Characterization of Hairless (Hr) and FGF5 Genes Provides Insights into the Molecular Basis of Hair Loss in Cetaceans

The study investigated the molecular basis of hair loss in cetaceans by analyzing the Hairless (Hr) and FGF5 genes across seven cetacean species. Researchers found that the Hr gene experienced functional loss, while the FGF5 gene was under strong positive selection, particularly in toothed whales, indicating its role in terminating the hair growth cycle. These genetic changes, likely under positive selection, contributed to the hairless phenotype in cetaceans, providing insights into their evolutionary adaptation to aquatic environments. The study highlighted the complex genetic mechanisms behind hair loss in cetaceans and the evolutionary pressures shaping these adaptations.