Old viruses resurrected

Thanks to advances in DNA technology, scientists can now reconstruct new copies of old viruses. Last year US scientists reconstructed the virus that caused the influenza epidemic of 1918. Now a team of French scientists has rebuilt a virus that infected our apelike ancestors million years ago. The scientists did not isolate a virus from a fossil. Instead, they examined vestiges of the virus that survive today within the human genome. About 100,000 segments of human DNA are remarkably similar to retroviruses. Retroviruses insert a copy of their genes into the genome of their host cell. Scientists estimate that 8 percent of the human genome is made up of this viral DNA, known as human endogenous retroviruses, or HERVs.

Many HERVs found in the human genome have counterparts in the genomes of other species. They infected our distant ancestors millions of years ago, and were passed down from generation to generation.

New year glitch for the shuttle

The shuttle Discovery was moved to the launching pad on Thursday to await a liftoff that could be as early as December 7, an effort to avoid potential New Year’s Eve computer glitches. The worry is that shuttle computers are not designed to make the change from the 365th day of the old year to the first day of the new one while in flight. NASA hasn’t had a shuttle in space on December 31 or January 1. “We’ve just never had the computers up and going when we’ve transitioned from one year to another,” said Joan E. Higginbotham, a Discovery astronaut. “We’re not really sure how they’re going to operate.”