Could newly uncovered DNA-elements be key in fighting climate change?

Assimilating genetic information from their hosts, Borgs are here to (potentially) act as our saviors! No, unfortunately, you didn’t just stumble into a really good Star Trek fanfiction. The Borgs that excite the scientific community today are magnitudes smaller than what you may already know.

Named after the spacefaring race of cyborgs from the Star Trek series, Borgs are actually large, linear sequences of DNA confirmed to exist in some archaea (non-bacterial, single-celled organisms) separate from their chromosomes. Primarily, these archaea belong to the species Methanoperedens, which can convert methane (CH4) into carbon dioxide (CO2) through a process known as methane oxidation. Surprisingly, a few of these Borg sequences have genes very similar to those in Methanoperedens for methane oxidation, in addition to a diverse set of genetic information seemingly unrelated to their current hosts. This suggests that Borgs have landed in Methanoperedens after assimilating genes from unknown former hosts long ago. Presumably, they have done the same to methane oxidation genes in modern-day archaea. With this in mind, scientists speculate that these Borgs may be significant in addressing a global issue: climate change.

Climate change has caught the attention of international policymakers and citizens alike. Warming oceans, extreme weather, and record surface temperatures have continually been at the forefront of global news, as it seems every other week involves some unfortunate meteorological record being broken. Primarily, climate change results from human activities. In 2021, humans emitted 36 billion tons of carbon dioxide, and 640 million tons of methane into the atmosphere. While carbon dioxide is the primary driver of human-caused climate change, methane is also an extremely potent greenhouse gas, as it is approximately 25-30 times better at trapping heat than CO2. Addressing climate change in the near term requires that we address methane levels in the atmosphere in addition to carbon dioxide emissions.

So, how do these novel Borgs show some promise in addressing methane emissions? To start, it’s important to highlight that Borgs exist outside of the Methanoperedens chromosome as an unprecedentedly large extrachromosomal element (any DNA that is not incorporated into host chromosomes). As a result, whatever genetic information Borgs hold can be expressed in parallel with genes from the host chromosome — assuming the host is capable of doing so. In other words, Borgs could allow some archaea to express more proteins, resulting in greater activity within the cell. Given that some Borgs are big enough to house the plethora of genes responsible for methane oxidation, this potentially provides some achaea increased metabolic capacity for the reaction compared to their Borg-free counterparts. There is also the possibility of upscaling this hypothetical phenomenon, creating archaea filled with multiple Borgs for even greater metabolic potency. These super methane-oxidizing organisms could be exploited to help us stave off and lower methane emissions by growing them in large quantities.

However, experiments still have to be conducted to confirm whether Borgs truly confer any beneficial effects on methane oxidation rates in archaea. As of now, researchers have only broken down the genetic makeup of a few Borgs. If scientists want to be sure Borgs function the way they are predicted to, their archaeal hosts would have to be cultured or grown in a lab setting — a process which has proven incredibly difficult to do due to archaea’s many unknown needs for growth. Despite this challenge, Borgs still excite scientists all around, especially Jill Banfield, professor of Environmental Science, Policy, and Management at UC Berkeley and principal investigator behind the study. In 2021, she tweeted on her team’s discovery of Borgs: “I repeat- I haven’t been this excited about a discovery since CRISPR.”

Future experimental evidence may demonstrate that Borgs are novel DNA elements imperative for increasing methane oxidation rates, simply just really large plasmids (an already well-known extrachromosomal element), or that they are senseless, floating strands of DNA. Still, this uncertainty from something scientists have never seen before is exactly why resistance to the Borg excitement is futile. Who knows, maybe sometime in the near future it will be tanks full of archaea that prevent climate change from breaking another dreadful record.