louse

The human louse is a wingless, blood-sucking parasite that lives its entire life on its host.

A genetic analysis based on louse DNA revealed the existence of two distinct clusters of lice that rarely interbred.

These people then spread south into Central America, where modern louse populations today still retain a genetic signature from their distant Asian ancestors.

“We can see the louse DNA reflected in our own history.”

For instance, only a single louse in the study came from Africa and relatively few came from South America, she notes, limiting the authors’ ability to infer how lice from around world relate to one another.