Thursday, January 5, 2012

Pulling genes from evolution


A research team at McGill University has been able to reach back into evolution to pull genes into current species.

They did the ground-breaking work with ants, introducing genes from so-called “supersoldiers” into three current species of ants.

In Pheidole (big-headed) ant colonies, there are millions of individual workers, including minor workers and soldiers.

Typically, depending on the food the ants are fed, certain hormones are triggered in the ant larvae and they either develop into soldiers or minor workers.

After unexpectedly finding supersoldier-like anomalies in Pheidole species in Long Island, where they aren’t normally seen, Dr. Ehab Abouheif and his team knew something unusual was going on.

“I’ve been collecting samples there for almost 15 years,” said Abouheif. “But when I saw them, I thought, ‘Holy cow! Those are monstrous looking soldiers!’ They look like the ones that are naturally produced in the American southwest.”

Researchers in Abouheif's lab, led by doctoral student Rajee Rajakumar and collaborators at the University of Arizona, then started trying to artificially induce the production of these supersoldiers. They did so by applying juvenile hormone to the ant larvae at critical stages in their development.

They had immediate success, producing supersoldier subcastes in at least three species in the genus where they have never been seen before – species that are widely separated in the evolutionary tree of Pheidole.

“These findings are groundbreaking for evolutionary theory,” says Abouheif, “because they show there is dormant genetic potential that can be locked in place for a very long time.

“The kind of environmental stressors that evoke this dormant potential are there all the time – so when the need arises natural selection can take hold of the potential and actualize it,” he says.

“So what we’re showing is that environmental stress is important for evolution because it can facilitate the development of novel phenotypes.

“Anytime you have a mismatch between the normal environment of the organism and its genetic potential you can release them – and these things can be locked in place for 30-65 million years.”

The research indicates ancient genes can be tapped for improving current species. 

The research was funded by Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair in Evolutionary Development Biology and the National Sciences Foundation’s Konrad Lorenz Institute Fellowship.