Scientists from The California Academy of Sciences have discovered that Demodex folliculorum, also known as "face mites," have evolved with humans over the years and through mitochondrial DNA analysis have revealed that they follow families and different human populations through the years. According to Michelle Trautwein, senior author of the study, increasing our understanding of these unique creatures can help us better understand human evolution and might even help us find a link between face mites and human health.
The tiny arachnids thrive in hairs throughout the human body and consume skin and oil cells. They exist in all kinds of places on the body from ears, eyebrows and eyelashes all the way to the hairs that cover nipples and genitals. Although the mites are harmless for most people, for some they can lead to various skin and eye disorders including rosacea and blepharitis.
"It's shocking that we're only just discovering how deeply our histories are shared with the mites on our bodies," Trautwein said in a news release. "They aren't just bugs on our faces, they are storytellers. Mites tell us about our own ancient history - it's a complex story, and we've only just scratched the surface."
The scientists studied 70 human hosts from around the world in order to understand why these mites vary with geographic location and examined the mite DNA and mitochondrial DNA of each of the mite's hosts.
"We discovered that people from different parts of the world host different mite lineages," Trautwein said. "The continent where a person's ancestry originated tended to predict the types of mites on their faces. We found that mite lineages can persist in hosts for generations. Even if you move to a faraway region, your mites stick with you."
The study was published in the Dec. 14 issue of the Proceedings of the National Academy of Sciences.
