Scientists have found molecules in the DNA of soil bacteria that do not belong to bacteria or eukaryotes, or viruses or plasmids.
The strange DNA molecules found in soil are unlike anything else. Scientists noted that they are very different from bacterial, viral, or other genes. In addition, they do not even look like plasmids. Recall that plasmids are small DNA molecules that are physically separated from chromosomes and capable of autonomous replication. Plasmids are mainly found in bacteria, as well as in some archaea and eukaryotes. Most often, plasmids are double-stranded circular molecules.
Biologists have named the strange DNA fragments “Borgs” – after the fantastic creatures from the Star Trek series. According to the plot, they were able to directly exchange genes with each other.
“Borges” discovered by scientists in soil samples from California are most likely elements of extrachromosomal inheritance, like plasmids. But if plasmids consist of a maximum of hundreds of thousands of nucleotides, then more than a million sequences have been found in the Borgs.
Sequencing of the Borgs showed that they contain genes characteristic of Methanoperedens. As you know, these are methanotrophic bacteria. Their task is to absorb methane and remove it from the atmosphere. Preliminary analysis has shown that the Borg is a metabolic tool for soil anaerobic bacteria. However, the authors of the work published in the bioRxiv preprint library note that more research is needed.