Overview

• A new study has revealed two distinct lice gene clusters that trace human migration to the Americas, one linked to original East Asian settlers, and another with European colonists.
• Lice and humans have been co-evolving for at least 25 million years. The genetic diversity of lice can provide key insights into human migration and evolution. For example, the divergence of head lice and body lice around 190,000 years ago is evidence that humans began to wear clothing during that period.
• The study included 274 head lice from 25 sites worldwide. Only 33 (12%) were hybrid lice - the result of intermixing between the lice of Native Americans and European colonizers. A significant 76% of these hybrids were found in the Americas, indicating that hybridization occurred in this region specifically.
• The two identified clusters of lice were distinct and rarely interbred. Cluster I was found globally, while Cluster II was located in Europe and the Americas. The lice with mixed ancestry from both clusters were predominantly found in the Americas.
• Future studies are planned which will include a larger body of research on the louse genome. This can potentially reveal more about lice evolution, their response to significant milestones in human history and culture, and even the louse-human speciation process.