Register for an account


Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.


Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.


Tiny Troublemaker, Giant Genome

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

By Boonsri DickinsonMay 8, 2007 5:00 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.

3 Free Articles Left

Want it all? Get unlimited access when you subscribe.


Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 50%


Already a subscriber? Register or Log In