By using a new technique to sample the DNA of microorganisms taken directly from the environment researchers have vastly expanded our knowledge of life on Earth, adding an astonishing 20 new phyla to the tree of life.
The incredible new study has shed light on 7,280 bacterial and 623 archaeal genomes. With roughly 80,000 genomes currently known to science, this latest paper alone has exploded this figure by a remarkable 10 percent. The study has been published in Nature Microbiology and could lead the way in uncovering what are termed “dark matter” microbes.
While we know that every single environment, from the sediments at hydrothermal vents to the guts inside us, are crawling with bacteria, we have only even been able to sample a minuscule amount of these organisms due to the inability to culture them successfully in a lab. Because of the fact we know they are there, that they are critical for the environment, and yet still cannot be described, they have been dubbed the “dark matter” of microbiology.
Typically “less than one per cent can be cultured, due to challenging factors including slow growth rates, fastidious growth requirements, and the need to cross-feed off other species,” explained Professor Gene Tyson, in a statement. So researchers have turned to other methods to sample these microbes.
New sequencing technology now allows scientists to recover microbial genomes directly from environmental samples in a technique known as metagenomics. For this, the researchers sample all the DNA sequences found in a soil sample, for example, and then piece them together using computational models to deduce what organisms are present. And it has turned up some astonishing results.
The authors of this latest work took 1,500 of these metagenomes that have already been uploaded onto a data base covering a huge range of environments, from the feces of baboons to sediment from the bottom of the oceans. Trawling through this, they were able to put together the genomes from a truly astonishing 7,280 bacteria and 623 archaea.
But what is more astonishing is the diversity that these genomes displayed. The researchers found that these covered 17 new bacterial and three new archaeal phyla. To give that some perspective, all flowering plants in existence belong to a single phylum, as to do all animals that possess a backbone.
The work paves the way for the technique to be carried out in other environments around the globe, constructing a comprehensive genomic repository of all microbial life. This could help in the discovery of new drugs and antibiotics that are so desperately needed in modern medicine.
[H/T New Scientist]