
Blood-sucking head lice have evolved alongside their human hosts so closely that their genes mirror waves of human migration into the Americas, a new study has found.
A genetic analysis of human lice (Pediculus humanus) from across the globe revealed a clear split between lice originating from Asia and those from Europe. In the Americas however, hybrids of Asian and European lice populate North and South America, while lice that first evolved in Asia dominate in Central America.