Lice DNA Provides New Insights into Human Migration and Colonization in Americas
Study reveals two distinct lice migrations to the Americas, one during the initial human crossing of the Bering Strait and another during European colonization; researchers call these parasites 'satellites' of human evolution.
- Contact between Europeans and Native Americans is recorded in the DNA of head lice, suggesting they arrived twice in the New World on human hosts. The first wave was during the original human migration across the Bering Strait, and the second occurred during European colonization.
- Researchers analyzed the genetic variation in 274 human lice from 25 geographic sites around the world. The study revealed two distinct clusters of lice that rarely interbred: one cluster had a worldwide distribution while the other was found in Europe and the Americas.
- The only lice with ancestry from both clusters are found in the Americas. This unique group appears to be a mixture of lice descended from populations that arrived with the First People and those descended from European lice brought over during the colonization of the Americas.
- A genetic relationship was identified between lice in Asia and Central America, supporting the idea that Asians migrated to North America, became the first Native Americans, and then spread south into Central America. Modern louse populations in Central America still retain a genetic signature from their distant Asian ancestors.
- Future research includes using different genetic markers to provide insights into more ancient events and developing new analyses to study other host-parasite systems. The researchers also plan to investigate potential louse interactions between early humans and Neanderthals.
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