Dark matter microbes similar to invisible particles believed to make up much of the universe have been found living on smartphones, a study has claimed.
A team of researchers from the University of California swabbed devices and shoes belonging to almost 3,500 people at sporting events in the US between 2013 and 2014.
So-called ‘dark microbes’ are more commonly found in extreme natural conditions such as boiling acid springs and underground aquifers but researchers found them present in more than 10 per cent of the samples.
Although scientists have made significant strides in understanding microbial life in the past two decades, very little is known about microbial dark matter.
A separate study from the University of Tennessee at Knoxville in 2018 found that dark matter is dominant in all major environments on Earth, with the exception of the human body, where most of the microbes have been cultured (grown and examined in a laboratory).
The team estimated that as many as a quarter of the microbes on earth could come from the roughly 30 phyla (a taxonomic classification between kingdoms and classes) of microbes that have never been cultured.
Dark microbes more prevalent than expected
Such microorganisms are extremely difficult to cultivate and study in lab settings, meaning the known dark microbe groups were discovered by scientists using genetic sequencing technology to search the world around us, amplifying DNA from the samples to identify major groups of bacteria.
“Perhaps we were naïve, but we did not expect to see such a high relative abundance of bacteria from these microbial dark matter groups on these samples,” said Professor Jonathan Eisen, of the UC Davis Genome Centre.
Armatimonadetes and Patescibacteria were among the dark microbe groups detected, bacteria generally found in soil and groundwater.
“A remarkable fraction of people are traveling around with representatives from these uncultured groups on commonplace objects,” said David Coil, lead author of the study and researcher at the university.
The report, published the in journal PeerJ, could hold significant implications for future breakthroughs in medicine, particularly in the case of culture-resistant bacteria.
Scientists believe some uncultured microbes are unable to grow in culture under lab conditions as they die if removed from their specific environments or delicate relationships with one another.
“Since these microbes provide many ecosystem services, such as helping crops grow and battling climate change, solving the considerable puzzle they’ve presented us is a crucial challenge for modern microbiology,” Karen Lloyd, associate professor in the University of Tennessee, Knoxville’s Department of Microbiology, wrote in the 2018 study.
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