Uptil now, the geneticists have been unaware of the mechanism by which new genes appear in a species. A research at the University of California – Davis has proved that the new genes come from the non-coding regions of the DNA.
Few years ago, David Begun, who conducted this research had found that new genes can be formed by the previously non-coding part of the DNA which rejects the previously held belief that new functions appear when existing genes are duplicated and diverge in function. But the new hypothesis is confirmed when scientists observed the production of new genes from the heterochromatin (the non-coding DNA region) in many plants and animals.
“This is the first example of totally new genes spreading through a species”, says Li Zhao, a researcher at UC Davis.
The research was carried out by scientists who observed the RNA-transcripts of corresponding expressed genes in the testis of the wild derived strains of the fruit fly Drosophila melanogaster and by comparing them to the transcripts expressed in the standard reference sequence strain and in two closely related species. Zhao found 248 new genes of which a hundred genes were already spread throughout the population.
The Emergence of these genes has been observed to be from non coding DNA when D. melanogaster split from its closest relative D. simulans. So, why did the new genes spread so fast in the population? The flies carrying these new genes gained preference in the reproduction (seen as potential mates carrying good genes), thus passing on their new genes to population.
Researchers plan to study other tissues, too. The reason for studying the gene production in testis is because testis have a high rate of adaptive evolution for male reproductive function.
Future researches that will be carried out on the basis of this research can further show how exactly does the new genetic material emerge. For now, scientists do not know if it could be because of a mutation arising in transcribed RNA that results in the expression of the non-coding DNA. Whatever the reason this phenomenon occurs, now it’s clear that the new genes which emerge from hetrochromatin if beneficial are selected by the nature to survive and spread throughout the species.
[Source: UC Davis | Image Credit: Ohtallinn.com]