"DNA Agrees With All the Other Science: Darwin Was Right"
discovermagazine.com
Molecular biologist Sean Carroll shows how evolution happens, one snippet of DNA at a time
by Pamela Weintraub; photographs by Saverio Truglia
(The Eyes Have it !)
So scientists were seeing the same master genes at work in many different species?
Yes. One shocking discovery was the relationship between our eyes and bug eyes. You wouldn’t think they had anything in common, right? Bug eyes, with 800 facets, work by different optical principles than human eyes. For almost a century and a half, biologists thought that they had evolved independently, from scratch, and that eyes had been invented many times in the animal kingdom by completely different means—different recipes in different groups of animals. We have now discovered that these eyes are formed by what is recognizable as the same gene, even though those animals have been evolving separately for 500 million years. When we took the mouse version of this gene—the same gene we find in the human—and put it in the fly and tweaked it, we induced fly eye tissue.
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. |
