Just in time for Valentine’s Day, researchers from Northwestern Medicine have discovered that the bacterium that causes the sexually transmitted infection of Gonorrhea, Neisseria gonorrhoeae, has taken up human DNA and incorporated it into its own genome. A gene sequence identical to an L1 DNA element found in Homo sapiens has been observed in Neisseria isolates from a laboratory in the Northwestern University Feinberg School of Medicine.
Certain viruses readily insert their genes into their hosts. In fact, over 50% of our DNA came from viruses—a fact interesting enough on its own. Unlike viruses and their hosts, however, bacteria and complex multicellular organisms are not known to be able to trade genes. This discovery, led by postdoctoral fellow Mark Anderson, reveals an evolutionary mechanism previously unheard of. Bacteria are normally only capable of acquiring genes from other bacteria in a process of genetic recombination similar in some respects with a popular method of celebrating Valentine’s Day. In doing so, bacteria obtain novel genes from their bacterial neighbors, which, if fortunate enough, could aid in their adaptation to their environment. As to what Neisseria, a pathogen found only in humans, is doing with the genetic fragment that it took, that is still currently unknown.
The research, which was published in the journal mBio, goes to further show that species barriers aren’t as cut and dry as most people would like to think. What are commonly seen as boundaries between dogs and wolves, monkeys and men, aren’t clear and distinct. Evolution shows our kinship to even the simplest of organisms.
I have this morbid curiosity if someone will eventually click 'Like' on this one, hehe 🙂
But seriously, what possible outcomes will it have on strains that do absorb human genes? Will future strains be able to slip past our immune systems better? Or does it merely randomize their gene pool to trigger haphazard mutations and let evolution take its course?
While it's unlikely that a mutation will ever completely fool our immune system, incorporating human genes could conceivably result in a more seamless exploitation of human hosts by pathogens. We don't know yet if Neisseria had a particularly targeted purpose for getting the gene fragment that it did and if does confer some sort of advantage, but natural selection will sort things out to see how this genetic heist by a bacterium will pan out.