A gene linked to cancer and neurological disorders could have come from plants through cross-species transfer. University of Adelaide, Australia, has conducted a study which was recently published in the journal Genome Biology.
Researchers at the University of Adelaide found in the largest study in the world that there are two “jumping genes” in 759 species of plants, animals, and fungi. According to their findings, researchers concluded that cross-species transfers were a frequent process throughout evolution.
Jumping Genes – Part of Our Evolution
The two genes are also called transposable elements. They are L1 and BovB, and they entered mammals as a DNA from the outside, explains David Adelson (University of Adelaide):
“Jumping genes, properly called retrotransposons, copy and paste themselves around genomes, and in genomes of other species. How they do this is not yet known although insects like ticks or mosquitoes or possibly viruses may be involved – it’s still a big puzzle. This process is called horizontal transfer, differing from the normal parent-offspring transfer, and it’s had an enormous impact on mammalian evolution.”
Adelson explains that jumping genes are more important than what’s in the existing DNA:
“Think of a jumping gene as a parasite. 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.”
Atma Ivancevic is a postdoctoral researcher at the University of Adelaide, and also part of the team of researchers that studied these jumping genes:
“L1 elements were thought to be inherited only from parent to offspring. 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.”
And then, they found a surprising thing: L1s can be found in plants and animals and sometimes in fungi. But the researchers found that two mammal species lack L1s: the Australian monotremes (platypus and echidna). This meant one thing: the gene spread to mammals after they diverged from monotremes, said Adelson:
“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.”
The other jumping gene – BovB – is a lot younger. It was discovered in cows, but it has jumped to reptiles, elephants, and marsupials. Previous studies led by Adelson shows that ticks facilitated the transfer of BovB between species.
Andre Blair s is the lead editor for Advocator.ca. He holds a B.A. in Psychology from the University of Toronto, and a Master of Science in Public Health (M.S.P.H.) from the School of Public Health, Department of Health Administration, at the University of North Carolina at Chapel Hill. Andre specializes in environmental health, but writes on a variety of issues.