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.
