Human-Louse Evolution

lice

Researchers study human evolution in many ways. New fossils are reshaping our understanding of human origins all the time. Genetic and genomic data suggest that modern humans may have interbred with archaic hominins during portions of our ancient past. Despite the considerable resources, financial and otherwise, spent studying human evolution, there are certain parts of our history that are murky and hard to reconstruct.

Researchers are now turning to sources of data beyond human fossils and human genetics to find new clues to our past. One strategy is to look at parasites of humans. In the Reed Lab we look at the evolutionary history of lice to infer things about human and primate evolutionary history. We can do this because primate lice have been evolving in tandem with their hosts for millions of years. The closest living relative of the human louse Pediculus humanus is found on chimpanzees.

Like chimpanzees and humans, these lice shared a common ancestor about 6 million years ago, and the head lice that live on humans today have been with us for a long time. Therefore, written in the DNA of human lice is yet another record of our past. For example, human head lice show the genetic signature of a population expansion out of Africa. We are currently funded to explore questions related to human migrations, such as when humans first arrived in the New World.