Face Off: your face is home to mites, and they've stuck with you for generations
- There are mites living on our face follicles
- These mites have been passed on for generations
More in the story
- What these mites can tell us about our ancestry and ethnicity
- These arachnids all have some connection to Africa
Mite, noun: A minute arachnid which has four pairs of legs when adult, related to the ticks. Many kinds live in the soil and a number are parasitic on plants or animals.
What the Oxford dictionary definition of mite won't tell you? These arachnids, more specifically the Demodex folliculorum, don't just live in the soil. They're comfortably housed in the hair follicles of your skin, more especially your face. And they might be key to understanding your ancestry, if you look back about a thousand odd years or so.
Different geographies tend to have different face mites in the population, indicating how the face mites have travelled over time and become intrinsic to certain races.
The findings are part of brand new research published in the American journal Proceedings of the National Academy of Sciences. The research was led by entomologist Michelle Trautwein of the California Academy of Sciences.
Researchers 'sampled' 70 people across the world "of diverse geographic ancestries" (European, Asian, African, and Latin American ancestries). As part of the sampling procedure Trautwein had to scrape their faces. For some volunteers a bobby pin was used across the forehead; with others, laboratory spatulas were used to obtain samples from the cheek and outer nose.
Next, the research team zoomed in on DNA from the mites' mitochondria (the energy-generating parts of cells) and looked for differences in the sequence - they worked upon 241 sequences from the mitochondrial genome and found four distinct groups, or 'clades', of mite mitochondrial DNA.
Based on just the DNA information of the mites, the lineage of the human subjects could be identified. "We found four major lineages," said Trautwein to Wired magazine. "And the first three lineages were restricted to people of African, Asian, and Latin American ancestry."
The fourth lineage was of European origin and stood quite distinctly apart, not showing the slightest blend with the mites of African, Asian, or Latin American origin.
It was clearly no easy task but for Trautwein, the findings are simply too incredible. "It's shocking that we're only just discovering how deeply our histories are shared with the mites on our bodies. They aren't just bugs on our faces, they are storytellers," he said to Daily Mail.
That statement is truer than you'd think. The story these invisible mites tell us is indicative of the very evolution of the human races across millenia. On further comparison of the DNA of the four lineages of face mites, researchers have concluded that the mite varieties started to diverge from one another between 2.4 million and 3.8 million years ago.
That fits in nicely with the time the genus of Homo was evolving on our planet. The research also found the African and Asian lineages were the oldest - giving credence to the widely-accepted idea that human beings as a species evolved in Africa before moving on to Asia and onwards.
However, moving away from a particular geography had little impact on the mites' distribution. The study showed that African-Americans living in the US for generations, for example, still hosted African mites that they may have received generations ago. Yet another nod to the theory that the roots of human beings can mostly be traced to Africa.
What's astounding is that these same mites which have been passed down generations and even from across continents years ago are still with us - or rather on us. As Trautwein tells Wired, "The fact that they're evolving on our face brings home this idea that evolution isn't this distant thing that happened in the past, or that's happening out there to something else... it's happening right here under our noses."
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