Author Topic: CRISPR Butterflies  (Read 238 times)


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CRISPR Butterflies
« on: September 25, 2017, 04:30:57 PM »
I thought of just adding this to the ongoing thread chronicling the development and use of CRISPR-Cas9, then decided that it's interesting for more than merely the use of the new technique to explore evolutionary pathways.

"Scientists Can Now Repaint Butterfly Wings" | The Atlantic


The wings on the left belong to a normal Gulf fritillary butterfly, and the ones of the right belong to one whose optix gene has been deleted.
Image Credit: Robert Reed

When the butterfly emerged from its pupa, Robert Reed was stunned. It was a Gulf fritillary—a bright-orange species with a few tigerlike stripes. But this butterfly had no trace of orange anywhere. It was entirely black and silver. “It was the most heavy-metal butterfly I’ve ever seen,” Reed says. “It was amazing to see that thing crawl out of the pupa.”

Reed’s team at Cornell University had created the metal butterfly by deleting just one of its genes, using the revolutionary gene-editing technique known as CRISPR.

[. . .]

Biologists have long been smitten by butterflies, and not just for their pretty colors. These insects are perfect subjects for addressing two of the most fundamental questions in the study of evolution. First, where do new things come from? Butterflies all evolved from a moth ancestor, so how did a presumably dull-winged insect give rise to a kaleidoscopic dynasty of some 18,000 species, each with a distinctive pattern of colors and shapes plastered on its wings? Also, what are the genes behind these patterns? How did a limited set of DNA come to produce patterns of such astonishing diversity and often-baffling complexity?

Many scientists, Reed included, have addressed that second question. By carrying out painstaking cross-breeding experiments, and by working out where in the wings various genes are active, they identified a handful of pattern-defining genes, with colorful names like optix, doublesex, and cortex. “It was convincing but we didn’t know exactly what these genes were doing,” says Reed. Without the ability to delete the genes, and see if their absence changed the butterfly wings, “we didn’t have the final proof. There’s been this frustrating wall that I’ve banged my head against.”

CRISPR changed everything. This technique, used by bacteria for billions of years and harnessed by scientists in the last five, allows researchers to cut and edit DNA far more easily and precisely than ever before. As I’ve argued before, the oft-cited concerns that CRISPR will usher in a dystopic era of designer babies are overblown. But scientists are already exploiting it, to do experiments that would have been impossible a decade ago. They’ve used CRISPR to probe the weaknesses of cancer cells, study how bodies are built, and to learn how our feet evolved from fishy fins. And Reed has used it to finally do the gene-deleting experiments that had long eluded him.

Common buckeye wings: normal (left) and with optix deleted (right)
Image credit: Robert Reed

[Continues . . .]

« Last Edit: September 25, 2017, 06:35:44 PM by Recusant »
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