Lice DNA records the moment Europeans colonized the Americas

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https://www.science.org/content/article/lice-dna-records-moment-europeans-colonized-americas

Lice DNA records the moment Europeans colonized the Americas

Genetics of head lice could offer a new avenue for exploring human migration and mixing

8 NOV 2023•2:00 PM ET•BYMICHAEL PRICE

When it comes to investigating the human story, scientists tend to focus on clues in our ancestors’ bones and artifacts. The tiny, bloodsucking parasites that infest our scalps? Not so much. But a new study published today in PLOS ONE suggests the genetics of head lice can shed light on when and where groups of humans split and came together in the past.

The authors present data suggesting European and American lice share a genetic affinity dating back to the European colonization of the Americas. Lice may even offer clues to ancient relationships not captured by human DNA or archaeological evidence, says Mikkel Winther Pedersen, a molecular paleoecologist at the University of Copenhagen who wasn’t involved in the study. “This could be a potential new angle to look at human migration and interactions.”

Head lice (Pediculus humanus capitis) cling to hairs and feast on blood from the scalp. They are an old foe; people around the world have complained about lice for thousands of years. Because head lice can only spread between people—and not from, say, human to rat or rat to human—they’re a good proxy for tracking human migrations, says the new study’s first author, Marina Ascunce, a molecular biologist at the U.S. Department of Agriculture.

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