Mysterious DNA strands that seem to accommodate genes from many different organisms have been found all around them in a California backyard.
Scientists have dubbed these elements “Borgs,” and their discoveries can help us not only understand the evolution of microorganisms, but also understand their interactions within their ecosystems and their role in the wider environment.
According to microbiologist Jill Banfield of the University of California, Berkeley, the Borg could make a very important discovery.
“I haven’t been excited about this discovery since CRISPR,” he said on twitter. “We found something mysterious, like CRISPR, related to the microbial genome.”
A sheet explaining the structure has been uploaded to the bioRxiv preprint server Pending peer review.
The first family of Borgs was found in mud dredged from Banfield’s backyard. He worked with geneticist Basem Al-Shayeb of the University of California at Berkeley to identify the virus that infects oxygen-starved microbes, known as archaea, that live in wetland environments, Science Magazine Report.
Ecological DNA is the best way to identify groups of organisms living in an ecosystem. But in the mud spoon, Banfield and Gray have discovered something funny DNA is made up of about a million base pairs. it’s big.
A closer look at the sequences revealed more distinguishing features: more than half of the genes were new; It has reverse order at the end of each strand; A consistent structure with self-replicating ability is demonstrated.
Confused, the researchers turned to the DNA database to see if they could find anything else similar to theirs. They identified 19 sequences that seemed to fit the profile.
What this DNA structure is is unclear, but they are certainly interesting. They belong to a class called Extrachromosomal Elemental structures, or ECE, which can be found on the outside of the chromosomes that contain most of an organism’s genetic material.
ECEs are large and self-replicating, and can be found inside or outside the cell nucleus; Examples include plasmids and viral DNA.
“We couldn’t prove they were primitive viruses, plasmids, or tiny chromosomes, nor could we prove they weren’t viruses.” The researchers wrote in their paper.
Borgs are much larger than other ECEs, however, According to Banfield: one third of the size of the host microbe.
Sequencing revealed that the burg they found had the same features as the genus Archaea called metanopyridin which oxidizes methane, suggesting that the structure may be associated with certain microbes. In fact, the Borg family could be critically involved in this process.
This is important to scientists like Banfield, because the process reduces the amount of methane in the atmosphere. Because methane is such a powerful greenhouse gas, studying how microbes do it could have implications for climate science.
However, metanopyridin It cannot grow in a laboratory environment – Not now. One problem with environmental DNA is that it can become contaminated with other genetic material in the same environment.
In fact, the Borg appears to have multiple genetic sequences of other elements and microbes. The researchers interpreted this to mean that the ECE had assimilated and internalized these genes and elements – hence the name, after an alien race of brain cells from Star Trek.
However, it is possible that shared genes are evidence of environmental pollution. For metanopyridin They can be grown in the laboratory, in isolation from the effects of such pollution, it is impossible to definitively state this genetic structure as a new discovery.
However, the results are interesting. If the Borg were real, they could increase the ability to metanopadryneAbility to oxidize methane. This suggests the possibility of an unknown process, and that this ECE plays a previously unknown role in atmospheric regulation.
“Borse carries many metabolic genes, some of which produce different types of Methanoperedens proteins that can have different biophysical and biochemical properties,” the researchers write in their paper.
“Assuming that this gene evolves and improves metanopyridin energy metabolism, the Borgs may have far-reaching biogeochemical consequences, including reduced methane fluxes, with important and unexpected climatic implications.”
The results are available on the bioRxiv preprint website.