Where Did Curly Hair Come From? Biological Anthropology May Provide Insights
Feb 21, 2025
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Tina Lasisi, a biological anthropologist at the University of Michigan, dives into the fascinating world of human hair evolution. She unpacks why humans have varying hair types, particularly focusing on the mystery behind curls. The discussion touches on hair's role in heat regulation and how environmental factors shape its characteristics. Lasisi also explores the impact of puberty on hair texture and interesting findings about "chemo curls," revealing much about how our hair reflects our biological stories.
Natural selection's influence on hair and skin illustrates how humans adapted to varying environmental factors and UV exposure.
Ongoing research into hair curl patterns reveals potential genetic markers and their implications for understanding human biology and health.
Deep dives
The Origins of Hair and Skin Variation
Natural selection and environmental adaptation play crucial roles in the variation of hair and skin among humans. Early ancestors likely lost body hair to regulate temperature but simultaneously became more vulnerable to UV radiation, prompting the evolution of darker skin in sunny regions due to increased melanin production. However, in areas with less sunlight, lighter skin evolved to facilitate vitamin D production, illustrating a complex relationship between skin pigmentation and environmental factors. This dynamic continues today as cultural adaptations, such as sunscreen and dietary adjustments, allow humans to navigate diverse climates without waiting for evolutionary changes.
The Complexity of Hair Curl Patterns
The reasons behind the various curl patterns in human hair remain largely unexplored, posing a challenge for researchers. Unlike skin color, which has measurable parameters like melanin content, hair curliness depends on multiple factors, and researchers have struggled to identify a definitive marker for categorization. A recent study demonstrated that tightly curled hair minimizes heat absorption from solar radiation, suggesting adaptive advantages linked to curl patterns. Determining the genetic and structural factors that dictate hair curl remains a frontier in biomedical research, with ongoing studies aiming to uncover the mysteries of human hair characteristics.
Future Directions in Hair Research
Understanding hair variation holds significant potential for insights into human biology and health. Research efforts are directed towards exploring how physiological changes, such as those during puberty or aging, affect hair characteristics, thus serving as markers for broader bodily changes. Additionally, hair analysis offers the possibility of monitoring physiological conditions through the detection of biomarkers like cortisol, providing a non-invasive means to gather health data over time. These avenues of research highlight the importance of hair not just as a physical trait but as a window into human physiological processes.
It’s fairly strange that humans, unlike many other mammals, don’t have hair all over. Our lack of body hair and wide geographic distribution led to the variation of sun-protective melanin in our skin. For the hair that remains, why did some groups develop curls while others did not? Biological anthropologist Tina Lasisi takes host Rachel Feltman through her work on understanding the roots of hair types. Plus, they discuss what we might learn from “chemo curls” and how developmental shifts change the extent and texture of hair during puberty.
Read papers on hair and thermoregulation published by Lasisi and her colleagues in 2024 and 2023
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Science Quickly is produced by Rachel Feltman, Fonda Mwangi, Kelso Harper, Madison Goldberg, Naeem Amarsy and Jeff DelViscio. This episode was hosted by Rachel Feltman. Our show is edited by Jeff DelViscio with fact-checking by Shayna Posses and Aaron Shattuck. The theme music was composed by Dominic Smith.