8 percent of human genes come from virus

Updated: Jan 08, 2010, 00:00 AM IST

Washington: Nearly eight percent of our genetic material comes from a virus and not from our ancestors, say US and Japanese researchers.

The research showed that the genomes of humans and other mammals contain DNA derived from the insertion of bornaviruses, RNA viruses whose replication and transcription takes place in the nucleus.

Bornavirus (BDV) owes its name to the town of Borna, Germany, where a virus epidemic in 1885 wiped out a regiment of cavalry horses. BDV infects a range of birds and mammals, including humans.

It is unique because it infects only neurons, establishing a persistent infection in its host`s brain, and its entire life cycle takes place in the nucleus of the infected cells.

Cedric Feschotte, biology professor at the University of Texas-Arlington (UTA) said this intimate association of BDV with the cell nucleus, prompted researchers to investigate whether they may have left behind a record of past infection, says a UTA release.

Feschotte wrote on a recent research led by Keizo Tomonaga, professor at Osaka University, Japan. Feschotte said this virally transmitted DNA may be a cause of mutation and psychiatric disorders such as schizophrenia and mood disorders.

The study and an accompanying article was published in `Nature`.