A Yale scientist suspects that a network of genes responsible for leg development was redirected to produce eye-spots on butterfly wings, a mutation that incidentally offered a survival advantage.

YALE (US)—Fossil records tell an incomplete story about our planet’s evolution, and increasingly scientists are looking to genomes to fill in the missing chapters.

Antonia Monteiro, an assistant professor of ecology and evolutionary biology at Yale University, believes genomics offers a window on evolution. “There are gaps in the fossil record,” she says, “that make it difficult to plot evolutionary change as a gradual process. How do you explain the sudden appearance of novel features, like feathers or hands, if transitional forms are missing?”

Monteiro studies genes that code for eye-spots, the concentric circles that have evolved on butterfly wings. She suspects that a network of developmental genes responsible for leg development has been redirected to produce patterns of pigment on the wing. This accidental mutation conferred a survival advantage on the butterfly, so it was passed on through subsequent generations.

“If networks of genes work and change together,” Monteiro explains, “a simple mutation might co-opt the network and enable it to act in a new way. So even if a form lacks a precedent in the fossil record, we might be able to find its origins in the genome.”

To test this theory, Monteiro is using transgenic tools to see if she can turn the eyespot gene network on and off. “Can we develop extra spots, or lose the spots altogether?” she wonders. “I’m hoping to show that complex traits, put together via the action of many genes, can actually arise by way of simple mutations.”

So far, functional genetic tests have been limited to five NIH model organisms. Expanding these techniques to a new species, Monteiro is pushing the limits of genomic science, even as she provides new ways to understand the origin of complex organisms.

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