Tiny Troublemaker, Giant Genome

A one-celled vaginal parasite sports more genes than its human host.

By Boonsri DickinsonMay 8, 2007 12:00 AM
T. vaginalis (green) adheres to a vaginal cell (pink) | Image courtesy of Harry Moore/ Nature


Sign up for our email newsletter for the latest science news

An international team of more than 60 researchers got a shock when they published a draft of the genome of Trichomonas vaginalis, one of the world’s most common sexually transmitted infections. Because T. vaginalis is a tiny single-celled protozoan that must hijack human cells to survive, it was expected to have a rather paltry genome. As it turns out, T. vaginalis has an astounding three times as many genes as its human host. “There was 10 times as much DNA as we originally thought there would be,” says Jane Carlton, who led the project while at the Institute for Genomic Research in Rockville, Maryland. No one is quite sure what all those genes are for, says Carlton. The parasite’s genome isn’t really that complex; it’s just repetitive. The recurring elements may relate to T. vaginalis’s evolution away from its ancestral home in the human intestine. “When the parasite moved from the intestinal tract to the urogenital tract, it increased in size, which may have something to do with the considerably expanded genome,” she says.

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Magazine Examples
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 70% off the cover price when you subscribe to Discover magazine.

Copyright © 2021 Kalmbach Media Co.