[NetBehaviour] Viral Fossil Brought Back to Life.

[marc]

Viral Fossil Brought Back to Life.

By Martin Enserink
ScienceNOW Daily News

In a controversial study, researchers have resurrected a retrovirus that 
infected our ancestors millions of years ago and now sits frozen in the 
human genome. Published online by Genome Research this week, the study 
may shed new light on the history of these genomic intruders, as well as 
their role in tumors. Although this particular virus, dubbed Phoenix, is 
a wimpy one, some argue that resuscitating any ancient virus is 
inherently risky and that the study should have undergone stricter reviews.

Retroviruses have the ability to make DNA copies of their RNA genomes 
and incorporate these into the host's genome. If this happens in a germ 
cell, the copy can be passed on to future generations. Indeed, the human 
genome is littered with the remnants of such human endogenous 
retroviruses (HERVs) (ScienceNOW, 29 September 2004). So far, 
researchers had been unable to recover a complete, functional HERV from 
a human genome however; part of the reason, they assumed, was that 
mutations accumulated over the millennia had rendered such viruses 
dysfunctional.

A team led by Thierry Heidmann at the Institut Gustave Roussy in 
Villejuif, France, near Paris, decided to try to awaken the ancestor of 
an entire family of HERVs called HERV-K(HML2). To "correct" for 
mutations, the researchers took dozens of known HERV-K(HML2) sequences 
and aligned them to create a so-called "consensus" sequence. Then they 
converted this information into a complete viral genome.

more...
http://sciencenow.sciencemag.org/cgi/content/full/2006/1101/4