A team led by the National Human Genome Research Institute in Bethesda, Maryland, sequenced the DNA of fungi living on the skin at 14 different body areas in 10 healthy adults.
Samples were taken from the ear canal, between the eyebrows, the back of the head, behind the ear, the heel, toenails, between the toes, forearm, back, groin, nostrils, chest, palm, and the crook of the elbow.
The data reveal that fungal richness varies across the body. The most complex fungal habitat is the heel, home to about 80 types of fungi. The researchers found about 60 types in toenail clippings and 40 types in swabs between the toes.
Other favoured fungal hotspots include the palm, forearm and inside the elbow. These had moderate levels of fungi, with each location supporting 18 to 32 types.
Mapping the body's fungi will help scientists figure out how to keep fungal communities—which are mostly friendly—from becoming harmful, for example, by turning into an infection.
Why do fungi have a foot fetish? As our lowest extremities, feet are cooler compared with the rest of our body and thus more attractive to cold-loving fungi.
Killing off all fungal hitchhikers is not always the best course of action, fungi have the important job of preventing disease-causing microbes from sticking to our skin.