Strange “Borg” DNA may have been assimilated by microbes for billions of years

Strange libraries of additional genes nicknamed “Borg” DNA appear to overload the microbes that possess them, giving them an uncanny ability to metabolize materials in their environment faster than their competitors.

By learning more about how organisms use these unusual extrachromosomal information packets, the researchers hope to find new ways to manipulate life to reduce a large part of methane emissions.

According to a study published last year (and now published in Nature) researchers have further analyzed the diversity of sequences that methane-eating microbes store in these unusual genetic depots to learn more about the evolution of life.

Named after the aliens from Star Trek, who assimilate other beings into a collective hive mind, these mysterious elements of DNA perform a similar trick, absorbing beneficial genes from many different organisms over long periods of time.

These genetic borgs were discovered in a methane consuming microbe called methanoperedensand it appears that over the millennia they have been able to self-optimize to enhance the organism’s ability to take up methane.

“Imagine a single cell that can consume methane,” says environmental scientist Kenneth Williams of Lawrence Berkeley National Laboratory in California. “Now you’re adding genetic elements within that cell that can use methane in parallel, and you’re also adding genetic elements that give the cell a higher capacity.”

“It basically creates a condition for methane consumption on steroids, if you will.”

Scientists believe Borgs are a form of DNA known as the extrachromosomal element (ECE). These packages of genetic material exist outside of the organism’s chromosomes and are equipped with tools that enable gene assimilation.

Unlike other ECEs, Borgs have a linear rather than a circular structure. They are also much longer than normal. In samples from underground soil, aquifers and riverbeds, the team discovered 19 different Borg ECEs, including four complete sequences.

Through advanced genomic analysis, Borgs have been found to match many of the methane-metabolizing genes methanoperedens themselves. In fact, some Borgs have all the mechanisms needed to eat methane themselves, provided they are in a cell capable of expressing the Borg’s genes.

The scientists theorize that Borgs could be leftover fragments of a variety of microbes absorbed by them methanoperedensthough not all methanoperedens Microbe contains Borgs. One explanation for this is that borgs act as storage for metabolic genes that are only needed at certain times – such as when there is a lot of methane around.

That would mean some methanoperedens Microbes can go beyond their normal ability to consume methane thanks to the presence of Borgs. However, there is still much to be unraveled about these intriguing bits of DNA.

“There is evidence that different species of Borg sometimes coexist in the same host methanopredens cell,” says environmental scientist Jillian Banfield of the University of California, Berkeley. “This raises the possibility that Borgs genes could spread across lineages.”

Researchers are now studying exactly how borgs can affect both biological (in the way cells develop) and geological (in the way additional methane is captured from the environment) processes.

It’s a long, long way — if we even make it — but perhaps one day microbes packaged in Borg could be engineered to significantly reduce annual methane emissions, a gas currently estimated to make up about 30 percent of human-caused global emissions Warming.

Parallel to the laboratory analysis, fieldwork is being carried out to learn more about how these extraordinary borgs work and to retrace a history that could potentially stretch into billions of years.

“Suppose these genes either reproduce methanoperedens energy metabolism or expand the conditions under which they can function, Borgs could have far-reaching biogeochemical consequences, with important and unanticipated impacts on climate,” the researchers write in their published article.

The research was published in Nature.