Anyone hoping to discover a new species may only need to look as far as the soles of their shoes or the phone in their pocket. A study of 3500 swab samples taken from people鈥檚 shoes and phones has found nine unstudied branches of bacterial life.
The samples were taken by Jonathan Eisen, of the University of California, Davis, and his team from members of the public attending sporting events, museums, and educational events in the US.
When they sequenced and analysed the DNA of the bacteria in each sample, they found that 35 different phyla of bacteria were present. Phyla are large branches of the family tree of life, and are subdivisions of the larger kingdoms, which include bacteria, plants or animals.
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According to official nomenclature lists, there are only 39 phyla of prokaryotic organisms 鈥� those that have small, bacteria-type cells that lack a true nucleus. But the team found nine possible additional phyla living on shoes and phones, suggesting that there is a vast variety of bacterial life that we know almost nothing about.
鈥淲e have only scratched the surface of understanding microbial diversity, even right in front of us,鈥� says Eisen.
The team found that 10 per cent of the samples they took contained DNA from bacteria belonging to such so-called microbial dark matter 鈥� organisms that we know little about because they are difficult to grow and study in the lab.
The samples also contained bacteria belonging to extremely rare groups, such as Edwardsbactera, first discovered in an underground water aquifer, and Diapherotrites, which was previously found in water seeping underground in an abandoned goldmine.
Some of the microbial dark matter, such as the enigmatic Rokubacteria, belonged to candidate phyla that have been previously proposed by research groups who have performed genetic sequencing of soils.
Sean Gibbons, a microbiologist at the University of Washington, who has also studied bacteria on everyday objects, says that unknown bacterial phyla are being identified every year thanks to recent advances in genetic sequencing methods.
鈥淏acterial species can spread across the planet faster than they can evolve into new species, which means that we don鈥檛 need to travel to far-flung deserts or the jungles to find them,鈥� says Gibbons. 鈥淭hese organisms, unknown to science, are under our noses, living on our phones or shoes.鈥�
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