For the past 50 years or so, biologists have thought of genes as the "bossy boots" on the playground of biological evolution and development. But Rich Palmer, professor in the University of Alberta's Department of Biology, suggests the real story is more complicated - that the dynamics involved are different in subtle, but significant, ways.
Evolution occurs through natural selection acting on genes. Random mutations in the genes of a plant or animal result in new traits. If a trait helps an organism survive and produce offspring, those genes are passed on to the next generation and the new trait spreads through the population.
Scientists have generally thought that behaviours develop based on an organism's genetic makeup. For example, it is generally understood that flat fish lie on their side on the ocean floor because a random genetic mutation caused one eye to migrate to the other side of their heads. In other words, genes are the leaders and the rest follows.
Palmer, however, flips this idea and argues for a "genes as followers" model - at least in some cases. His argument can be best explained through his own work on the question, which focuses on what's called "left-right asymmetry."
Palmer is studying why organisms, including humans, develop asymmetrically. In humans, for example, we have a dominant and a non-dominant hand - one we use for writing and one we use to hold the phone. These kinds of paired structures are common in nature.
Lobsters, for example, have two different kinds of claws. "The crusher claw is mostly slow muscle and big molar teeth. It generates force. The small claw is all fast muscle and is more dexterous," Palmer explains.
Unlike adults, baby lobsters have two small claws, with no hint of a big claw. What's astonishing, says Palmer, is that the crusher claw appears only once the lobster starts to use one claw more than the other. He believes the behaviour is the leader here, triggering the genetic program to develop the more frequently used claw into a crusher claw.
While all lobsters today have the genes to develop a crusher claw, Palmer believes it's possible that, at a distant time in evolution, crushing prey with one claw instead of the other began as a behaviour without a genetic basis.
"I have a hunch that a lot of asymmetries start out as useful behaviours. Even if you have two claws of the same size, you're going to use one to hold the prey and the other to crush it. And when genetic variance to support that behaviour arises, it is immediately selected for. That's a 'genes as followers' argument.
"It's not a very popular view," admits Palmer. Then, after a moment, he adds, "Yet."
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