Researchers studying portions of the genome containing 'retroelements,' also known as junk DNA, found many copies of a gene sequence in the chimp and gorilla genome that didn't appear anywhere in the human genome. They translated that genome sequence into its corresponding protein, and discovered that it was the remnant of a retrovirus, a type of virus that copies its genetic information into the host's genome. Evidence suggests that the 'retroelement' originated from an external retrovirus that actively infected ape species in the past.
"The reason retroviruses are so deadly, at the genetic level, is that they have a tremendous potential to mess up a gene and interfere with its expression," explained Dr. Evan Eichler, UW associate professor of genome sciences and co-author of the study. "That can have negative effects. It's a double-whammy: the virus infected and possibly killed off some of the population, but also caused genetic errors in survivors. Those errors would have later eliminated more of the population."
The virus had invaded the genome in the germline -- in sperm or egg cells -- allowing the sequence to be passed on to future generations. In those animals in which the virus was taken up next to or inside a gene -- in the part of the genome that codes for the most important biological functions -- the virus had an even stronger effect.
What researchers don't understand is why t
Source:University of Washington