Biologist Hopi Hoekstra on the extended phenotype, structure of mice burrows, and addiction encoded in genome
To what degree is an animals behavior determined by their genes versus their environment? How did ideas from Richard Dawkins’ book “The Extended Phenotype” become the basis for behavioral studies? Professor of Zoology at Harvard University, Hopi Hoekstra, explains how constructing burrows can be connected to genetics.
One of the main questions that motivates us is trying to identify genes that are responsible for naturally occurring behaviors, because there are some fundamental questions in the field of behavior that are still unanswered. For example, for any occurring natural behavior how much of that behavior is controlled by genetics versus the environment? What are the genes that are involved? How do those genes work to produce variation in behavior? Do these genes have a role in developming our neural circuitry or is our neural circuitry constant and just modulating to make those behaviors different?
Some examples of extending phenotypes are the web of a spider, nest of a swallow. For example, swallow’s nest in a particular species tends to have a very similar shape, is made of very similar material, positioned in a very similar type of place, compared to the sister species, which may produce a different shape, position and have a different material composition.
We suggest that you can get complex behaviors by putting together the different genetic modules. The other thing that was quite surprising for us was that there are three regions that control the length and the entrance tunnel, each of them individually contributes about three centimeters. If you take the region of the genome from the long burrowing parent and put it into the background of short burrowing parent you are going to get a burrow that is three centimeters longer.