Our team showed that the same common gene is critical to
building limbs in humans and fruit flies. It turns out that this
gene is critical to building virtually everything that sticks
out of the body: antennae, legs, horns, whatever. These kinds of
experiments shattered our preconceptions and forced people to
think differently. Beneath these extremely diverse exteriors was
a deeply shared common genetic tool kit. If I had five minutes
with Charles Darwin, I’d start right there. It would blow his
mind. Clearly we have entered the age of experimental Darwinism.
What are the experiments like, specifically? We look at lots of
species to figure out the ancestral form of a particular
molecule. We can reconstruct that ancestral molecule and then
retrace the steps that must have taken place to forge the new
forms and functions we see today. If you think that the
difference between two species involves changes in certain
genes, you can swap those genes between the species. We’re doing
those experiments trait by trait.