Variation in Human Hair Ultrastructure Among Three Biogeographic Populations

The study investigated the ultrastructure of human scalp hair, focusing on the density and distribution of melanosomes, cuticle thickness, and the relationship between hair fiber ultrastructure and biogeographic ancestry. Using transmission electron microscopy (TEM), the researchers analyzed hair cross-sections from three metapopulations: European, African, and East Asian. They found significant variation in hair cross-sectional shape, cuticle dimensions, and melanosome distribution, with these traits showing statistically significant patterns related to ancestry. The results contribute to a better understanding of human hair morphology variation and lay the groundwork for future research on the genetic and developmental factors influencing hair ultrastructure.