Human DNA found in gonorrhea genome

EVANSTON, Ill., Feb. 14 (UPI) -- U.S. researchers say they have found the first evidence of a transfer of human DNA to a bacterial genome -- in this case, the bacterium that causes gonorrhea.

Researchers at Northwestern University say this is the first evidence ever seen of a direct transfer of DNA from human to bacteria, a university release said Monday. Scientists say the discovery offers insight into evolution as well as gonorrhea's singular ability to continually adapt and survive in its human hosts.

Gonorrhea, transmitted through sexual contact, is one of the oldest recorded diseases and one of a few that are exclusive to humans.

"This has evolutionary significance because it shows you can take broad evolutionary steps when you're able to acquire these pieces of DNA," Hank Seifert, Northwest professor of microbiology, said. "The bacterium is getting a genetic sequence from the very host it's infecting. That could have far reaching implications as far as how the bacteria can adapt to the host."

Scientists have long known of gene transfers between different bacteria, and even between bacteria and yeast cells.

"But human DNA to a bacterium is a very large jump," researcher Mark Anderson, a postdoctoral fellow in microbiology, said. "This bacterium had to overcome several obstacles in order to acquire this DNA sequence."

Anderson also performed a DNA screening on the bacterium that causes meningitis, Neisseria meningitidis, which is very closely related to the Neisseria gonorrhoeae bacteria at the genetic level. There was no sign of the human fragment, he said, suggesting the gene transfer is a recent evolutionary event.

"The next step is to figure out what this piece of DNA is doing," Seifert said.