2006 NSERC Steacie Fellow Locke Rowe

Getting beneath the surface of evolution

The view from the edge of a pond might look peaceful enough, but Locke Rowe has a different perspective. He sees the subtle interplay of genetic forces that underlie sustained competition not only between species, but also between the sexes.

What caught his eye, early in his career as an evolutionary biologist, was the behaviour of water striders. These common insects, delicate enough to be supported by the water’s surface tension, have cultivated some downright predatory reproductive strategies pitting male against female.

For instance, over time, male water striders have evolved elaborate appendages to grasp and hold a female during mating. For their part, females have evolved counter-strategies for resisting the grasp of males, which could otherwise leave them vulnerable to attack by other predatory insects in the water.

“The picture is one of a co-evolutionary arms race driven by sexually antagonistic selection,” says Dr. Rowe, whose laboratory at the University of Toronto has been at the forefront of burgeoning scientific interest in how, over evolutionary time, this antagonistic selection has molded the differences between the sexes that we see today.

Holding the Canada Research Chair in Evolutionary Ecology, he has been studying the biological foundations of this interplay between the reproductive traits maintained by members of each sex, as well as other developmental phenomena.

“My scientific interests centre on the evolution of life histories,” he says, posing some of the questions that have animated his research for more than a decade. “Why do most organisms senesce? What maintains the abundant genetic variation that fuels evolution? How does each sex determine the evolutionary pathway that the other follows?”

Having turned the water strider into a poster bug for evolutionary dynamics, Dr. Rowe now wants to adopt a candidate gene approach (CGA) to explore the genetic roots of such developments. This technique, which he would like to complement with micro-array studies of gene expression, attempts to isolate those genes that are directly linked to the appearance of specific traits in an organism.

“Recent advances in genomic techniques and databases, and abundant expertise at the University of Toronto make both the CGA and micro-array approaches achievable,” he says. “It is time to extend the emerging techniques of genomics to a natural model system, where we know much about antagonistic selection and co-evolutionary change, but little about the genetic mechanisms underlying them.”

As one of six 2006 Steacie Fellows, he intends to do just that. By taking a closer look at the role of sexual selection within the evolution of species, he proposes to take the large compendium of genomic information that has already been assembled in laboratories and apply it to insects in their natural habitat.

“Most of this kind of research is done on the mouse or the fly, the standard laboratory models,” he says. “Given what he has already revealed about the curious life of the water strider,” he adds, “it should make for an even more interesting model.”

And while this new direction may take him a little bit further into the laboratory, Dr. Rowe emphasizes that his inquiry remains firmly rooted in the field, “observations of natural history – sitting by a pond watching these things, and trying to understand what was going on as they interacted.”