Scientists in the US have made a breakthrough in microbiology that represents a major step “towards a better understanding of biological evolution on our planet”.
The findings, published in the journal Nature, involve the genetic sequencing of hitherto almost entirely unexplored branches of the tree of life, in an area known as “microbial dark matter”.
Attempts to research the precise nature of whole swathes of single-celled microorganisms, the most diverse and abundant variety of species on Earth, had been limited by the fact that they are notoriously difficult to reproduce in a laboratory.
This is despite the fact that they are known to thrive in the world’s most hostile environments, including the polar ice, the driest parts of deserts and the deepest stretches of the oceans.
But scientists have been able to use new technology to work from just a single cell of a microbe and then sequence its complete genetic code.
The report said they had successfully applied the technique to 201 different species of microorganism, and said that: “Genome sequencing enhances our understanding of the biological world by providing blueprints for the evolutionary and functional diversity that shapes the biosphere.”
The California-based team said they were able to “challenge established boundaries between the three domains of life” – made up of single-celled archaea and bacteria, and more complex eukaryota which include animals, plants, and the majority of other organisms we are familiar with.
Phil Hugenholtz, a contributor to the research and director of the Australian Centre for Ecogenomics, told the BBC: "For almost 20 years now we have been astonished by how little there is known about massive regions of the tree of life. This project is the first systematic effort to address this enormous knowledge gap.”
The scientists said they had found unexpected metabolic features in both archaea and bacteria, which “extend our understanding of biology”.
They nonetheless acknowledge that the research is just a beginning, given estimates that there are many millions of different microbe species. They said they believed a further 16,000 genomes from all over the world would need to be sequenced if we are to have an understanding of just 50 per cent of the different “phyla” – branches of species – that exist on the planet.