Making Waves with Hairs: Genetic and Epigenetic Factors in Hair Pattern Formation

The document from 2004 examines the formation of hair patterns on the skin, emphasizing the role of both genetic and epigenetic factors. It references a study by Ziering and Krenitsky that identified five distinct hair whorl patterns in a sample of nearly 500 males, noting variations across different ethnic groups. The paper also discusses the dynamic nature of hair growth patterns in mice and suggests that hair waves may be related to patterning events over time. The Belousov–Zhabotinskii reaction is proposed as a model for understanding these patterns, with the skin oscillating between pigmented and non-pigmented states. The document concludes that skin patterns are the result of simple reaction-diffusion mechanisms and that understanding the physical–chemical laws governing these patterns is essential for a comprehensive understanding of biological morphogenesis.