University of Missouri plant scientists found that mobile DNA can play an important role in plant adaptation.
"Mobile DNA has the potential to make profound changes in plant genomes, and that has an effect on the plants' ability to adapt and survive in different environments," said Timothy Vision, curators' distinguished professor of plant sciences and director of the Christopher S. Bond Life Sciences Center at MU. "Plants with more mobile DNA are more likely to have new genes that can confer advantageous traits, such as disease resistance or tolerance to drought or heat."
Plant physiologist Vision also found mobile DNA can help plants avoid the negative consequences of inbreeding.
"Plants often reproduce by self-fertilization, which is akin to human incest. The problem is that inbreeding can lead to genetic defects, just like it can in humans," said Vision. "Interestingly, we found that plants with more mobile DNA were better able to avoid the deleterious effects of inbreeding than plants with less."
Evolutionary biologist Austin Mast found mobile DNA can also be adaptive and provide fitness benefits to animals as well.
"Many transposable elements are often thought to be useless DNA parasites, but we found transposable elements can actually help a species thrive in certain environments," said Mast, an assistant professor in the Department of Biological Sciences at MU. "For example, we found that the fruit fly populations were more likely to survive and reproduce when transposable elements were present compared with populations that lacked transposable elements."
Vision and Mast explained the benefits of mobile DNA come at an evolutionary cost.
"The benefit of mobile DNA is that it can create new genes relatively easily," said Mast. "However, this can also be problematic because the vast majority of changes that transposable elements cause are likely harmful. Most transposon-induced mutations are likely to impair gene function to the extent that a new variant will be deleterious and therefore eliminated from the population. So the evolutionary turnover is exceedingly high for transposable elements, and many evolve to spread through the genome more than others. Despite the potential negative evolutionary aspects of transposons, our work found there can be a net fitness advantage to having more transposons."
The researchers explained their work sheds new light on how mobile DNA can be a driving force behind evolution and the fitness of some species over others.
"The story of how transposons and hosts evolve together is a fascinating one," said Mast. "Transposons are often seen as the scourge of the genome, but our research shows they can actually be beneficial to the host when the host is in a changing environment."
