The genetic diversity of tiny face mites (Demodex folliculorum), which have evolved along with humans, may be linked to the dispersal of humanity, scientists say.
The new paper – published December 14 in the Early Edition of the journal Proceedings of the National Academy of Sciences – stated that the various lineages of face mites are evidence of where their ancestors lived. Face mites evolved along with humans who at one point started their migration across the globe.
Michelle Trautwein, senior author of the study and an entomologist at California Academy of Sciences, said that the arachnids that live on our faces, and that have coexisted with humans from the very beginning, can tell a lot about us and our own history through their genes.
Demodex folliculorum is one of the parasitic mites that can be found on people’s faces. The overpopulation of Demodex folliculorum is an infestation called demodicosis.
Europeans typically host only one lineage of mites, compared with those from Asian, African, or Latin American ancestry who have a greater variety of face mites, according to the researchers.
Dr. Trautwein said that the oldest face mite lineages live on people of Asian and African ancestry. That coincides with the theory that humans migrated out of Africa. A lot of people agree that humans first emerged in Africa, before they trekked to different parts of Eurasia.
In the study, the researchers took samples from 70 people who were either born in the United States, immigrated to the U.S., or were just visiting. They then extracted and sequenced the mites’ DNA. Using the mitochondrial DNA, the researchers mapped the lineages of the mites.
George Perry, the principal investigator for the Anthropological Genomics Laboratory at Pennsylvania State University, said that he is curious to find out why Europeans or people of European ancestry lack diversity among face mites.
In 2014, Perry found other parasite that could be linked to human evolution. For instance, bedbugs, which initially lived on bats, found their way to humans when people began using bedding to sleep in caves.
Lice were also drawn to ancient human once they started using clothing. In both of these scenarios, parasites tell us about human evolution or a change in human behaviour.