Red Hair and Disease Risk Shaped by Thousands Years of Selection: DNA Study

Human evolution hasn’t stopped; it has actually sped up since the dawn of agriculture. A landmark genetics study of 16,000 ancient human remains and 6,000 living individuals has revealed that biological selection has actively shaped our DNA over the last 10,000 years.

The research published in the journal Nature, identified 479 genetic variants that have been "favored" by natural selection in West Eurasia. Among the most notable winners are genes for red hair and fair skin. Scientists from Harvard University suggest these traits became more common because they allowed ancient farmers in northern climates to produce Vitamin D more efficiently despite low sunlight and changing diets.

However evolution is a double-edged sword. The study found that genes increasing the risk of coeliac disease and tuberculosis actually became more frequent over thousands of years. Researchers believe these variants might have offered hidden protection against other deadly pathogens common at the time helping ancestors survive long enough to pass on their genes.

Conversely, "thrifty genes" that help the body store fat once vital for hunter-gatherers facing famine are now being selected against. In a world of stable food supply through agriculture these once-helpful traits have become a biological disadvantage.