How Ancient Viruses Invaded Our Genomes --New Clues Discovered

[MindMover]

Scientists have uncovered clues as to how our genomes became riddled with viruses. The study reveals important information about the so–called 'dark matter' of our genome. For years scientists have been struggling with the enigma that more than 90 percent of every mammal's genome has no known function. A part of this 'dark matter' of genetic material is known to harbour pieces of DNA from ancient viruses that infected our ancestors going back as far as the age of the dinosaurs.

Researchers at Oxford University, the Aaron Diamond AIDS Research Center in New York and the Rega Institute in Belgium wanted to know how these ancient viruses got into their hosts' genomes in such abundance.
The team searched the genomes of 38 mammals covering a large range of species: from mouse, rat and bat to human, elephant and dolphin. Genetic material from all of the residing viruses was collected and then compared using mathematical models.

The findings revealed that one particular group of viruses had lost the ability to infect new cells. Their genetic material is still able to amplify itself but the whole lifecycle of the virus is passed within a single cell. This change, they found, was followed by a dramatic proliferation of the virus' genetic material within the genomes.

A comparison with all of the other viruses in the genomes revealed this to be a universal phenomenon, and that loss of cell infectivity is associated with a roughly 30-fold increase in the abundance of the virus.

http://www.dailygalaxy.com/my_weblog/2012/04/mystery-solved-how-ancient-viruses-riddled-our-genomes.html

[Warpy]

1. I've often thought that viruses were one of the mechanisms

of evolution. They have, in fact, traced the transition between egg laying to live birth in sheep to a virus introduced to a remote ancestor. This is just one more piece of that puzzle.

It also explains why evolution is discontinuous, happening in bursts rather than slowly over a long period of time the way natural selection predicted. It's why species (like ours) underwent rapid changes and then remained stable for long periods.

Most viruses that lost their ability to infect and became part of the genome are likely junk data. Some have proven remarkably useful, IMO.

[MindMover]

2. thank you for your opinion.