Lice tell mankind's story

A new study of the phylogeny of human head and body lice provides evidence that Homo sapiens once made direct physical contact with a more archaic lineage. The findings, published in PLoS Biology this week, show how humans' evolutionary past can be pieced together by understanding what happened to our closely co-adapted parasites, say the authors.

Modern humans—Homo sapiens—are generally thought to have passed through a tight population genetic "bottleneck" somewhere between 10,000 and 20,000 years ago. Parasites such as lice tend to be highly species specific, so by unravelling their evolutionary history it's possible to see past the bottleneck, according to the Florida Museum of Natural History's David Reed, lead author of the paper.

"The addition of parasite data to studies of primate and human evolutionary history is similar to having multiple camera angles recording an event," Reed told The Scientist. "We aim to create a better picture of ...