Unexpected Viral "Fossils" Found in Vertebrate Genomes Ancient
Viral Sequences May Protect Against Infection PHILADELPHIA (July
29, 2010) – Over millions of years of evolution, retroviruses,
which insert their genetic material into the host genome as part
of their replication, have left behind numerous bits of their
genetic material in vertebrate genomes. Now, in an unexpected
discovery, a team of researchers reports that human and other
vertebrate genomes also contain many ancient sequences from two
deadly virus families. Because neither virus family inserts
their genetic material into the host genome during replication,
as retroviruses do, the discovery was unanticipated. The
conservation of some of these sequences over evolutionary time,
however, suggests that they must give the host a selective
advantage, perhaps protecting them from future infections by
viruses from those families. "This was a surprise for us," says
Anna Marie Skalka, PhD, Director Emerita of the Institute for
Cancer Research at Fox Chas