Sean Carroll’s most flamboyant finding was prompted by an innocent query before a seminar. Carroll had gone down to Duke University to give a talk about his research on the genes and molecules that direct the regular spacing of bristles on a fruit fly leg. There he met up with Fred Nijhout, who had been studying the spots on butterfly wings. “Fred asked, ‘Do you think the things you’re working on could explain these patterns, too?’ And he shows me a bunch of butterflies,” says Carroll. “I said, ‘I don’t know, Fred. It’s a big question.’ But it haunted me.”
So Carroll asked Nijhout for some butterflies. And he set out to do the same sort of rigorous analysis he’d been conducting on Drosophila. “This was in the early days—1991,” he says. “So there were no genomic resources. Just old fashioned molecular biology.” His team isolated the butterfly counterparts of ...
