Deadly Viruses: Part of Us for Millions of Years

[Guest guest]

Deadly Viruses: Part of Us for Millions of Years

Over the past few months, researchers have found that the viruses

responsible for Ebola, Marburg hemorrhagic fever, and other deadly

diseases have been hanging out in the genomes of certain mammals for

tens of millions of years. It turns out that this was just the tip of

the iceberg. Scientists

have now discovered that these viruses have integrated themselves into

the DNA

of a wide range of animals, including humans, zebrafish, and other

vertebrates.

Although the researchers don't know whether the embedded viral sequences

have a function, they suspect they are helpful to the

animals--otherwise,

they wouldn't have endured through millions of years of evolution.

The viruses in question belong to two families: Filoviruses, which

include

Ebola and Marburg, and Bornaviruses, which causes neurological diseases

in

certain animals, such as horses. All are RNA viruses, which means they

can't easily convert their genetic material into DNA, a necessary step

for

integrating into an animal's genome. Yet they've done just that, and the

new

study suggests that they've been even more successful than scientists

imagined.

http://snipr.com/1076g9