Your Face Mites May Reveal More about Human Evolution and Migration

First Posted: Dec 16, 2015 06:16 AM EST

We know very little about the mites that live on our face and in our hair. But now, scientists have found that they may be extremely loyal. Researchers have discovered the face mite evolved with us over millions of years.

Improving our understanding of mites that live in human hair follicles and elsewhere may allow scientists to pinpoint the mites' role in human health. Dubbed "face mites," these animals are actually tiny arachnids that inhabit hairs throughout the human body and consume skin cells and oils. They exist in human ears, eyebrows, and eyelashes as well as hairs that cover nipples and genitals.

For most people, mites are harmless. However, for some mites can be associated with skin and eye disorders, such as rosacea and blepharitis. This is one reason that scientists need to learn more about these constant human companions.

"It's shocking that we're only just discovering how deeply our histories are shaped with the mites on our bodies," said Michelle Trautwein, one of the researchers, 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 researchers sampled 70 human hosts from around the world. The scientists then sequenced mite DNA to look at the mitochondrial DNA of each subject's mites.

"We discovered that people from different parts of the world host different mite lineages," said Trautwein. "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 findings reveal that some mite populations are better able to survive and reproduce on hosts from certain geographic regions. Differences in mite lineages are consistent with the divergence of human populations and support the "Out of Africa" hypothesis. In addition, mites aren't shared easily; instead, they are shared primarily with our family.

The findings are published in the journal Proceedings of the National Academy of Sciences.

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TagsMites, Face, Human, Humans, Evolution, Health, Migration, DNA