CANBERRA, July 9 (Xinhua) -- The transfer of genes between species has significantly influenced the genetic makeup of mammals, an Australian study has found.
The University of Adelaide study, published in the journal Genome Biology on Monday, tracked two transposable elements, commonly known as "jumping genes," across 759 species of plants, animals and fungi.
Researchers found that the two elements -- Line-1 (L1) and BovB -- frequently transferred between species, driving evolution.
It marks the first time that a study has proved that the L1 element has jumped between species.
"L1 elements were thought to be inherited only from parent to offspring," Atma Ivancevic, lead author of the study, said in a statement on Monday.
"This process is called horizontal transfer, differing from the normal parent-offspring transfer, and it's had an enormous impact on mammalian evolution."
"Most studies have only looked at a handful of species and found no evidence of transfer. We looked at as many species as we could."
David Adelson, head of the University of Adelaide's Bioinformatics Hub said the study, the largest of its kind, found that 25 percent of the genome of cows and sheep is derived from jumping genes.
"Think of a jumping gene as a parasite," he said.
"What's in the DNA is not so important -- it's the fact that they introduce themselves into other genomes and cause disruption of genes and how they are regulated."
While L1s were prominent in most mammal species, their absence in the genomes of two Australian monotremes -- the platypus and the echidna -- established that the gene entered the mammalian evolutionary pathway after monotremes diverged from that pathway.
"We think the entry of L1s into the mammalian genome was a key driver of the rapid evolution of mammals over the past 100 million years," Adelson said.
