Biology

Butterfly wing patterns altered with CRISPR offer insights into evolution of biodiversity

Butterfly wing patterns altere...
CRISPR technology has allowed scientists an entirely new way to understand genes and evolution
CRISPR technology has allowed scientists an entirely new way to understand genes and evolution
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The left side of this Painted Lady butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
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The left side of this Painted Lady butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
The left side of this Monarch butterfly show how a typical specimen would look in the wild, while the right side shows the effects of CRISPR gene editing
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The left side of this Monarch butterfly show how a typical specimen would look in the wild, while the right side shows the effects of CRISPR gene editing
The left side of this Sara longwing butterfly represents show how a typical butterfly's wing looks, while the right side shows the effects of CRISPR
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The left side of this Sara longwing butterfly represents show how a typical butterfly's wing looks, while the right side shows the effects of CRISPR
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A closer look at the George Washington research
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A closer look at the George Washington research
A Zebra Swallowtail butterfly feeds in Arnaud Martin’s lab
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A Zebra Swallowtail butterfly feeds in Arnaud Martin’s lab
CRISPR technology has allowed scientists an entirely new way to understand genes and evolution
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CRISPR technology has allowed scientists an entirely new way to understand genes and evolution
A closer look at the George Washington research
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A closer look at the George Washington research
The left side of this Speckled wood butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
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The left side of this Speckled wood butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
The left side of this Junonia butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
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The left side of this Junonia butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
View gallery - 17 images

Two newly published complimentary studies have utilized CRISPR genome editing technology to explore how specific genes affect wing pattern variation in butterflies. By selectively knocking out single genes and observing the effects, scientists have uncovered a key insight into how broad biodiversity can evolve.

The studies focused on two genes previously identified as being key in butterfly wing pattern development. Called WntA and optix the researchers have described these as "painting genes" and across several experiments they observed what happens in different butterfly species when each gene is selectively switched off.

A team at George Washington University examined the WntA gene and discovered that the gene had significantly different patterning effects across various butterfly species. In some species silencing the gene affected the development of stripe-like patterns, while in other species the gene controlled the boundaries between different color fields.

The left side of this Junonia butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR
The left side of this Junonia butterfly shows a typical specimen's wing, while the right side shows the effects post-CRISPR

More generally, the gene could be seen to direct the borders of the patterns in each individual butterfly species. Speaking to Nature, one of the lead authors of the study Arnaud Martin explains, "It's laying the background to be filled in later. Like color by numbers or paint by numbers. It's making the outlines."

The second study, from Cornell University, focused on the optix gene, and after knocking it out in four species using CRISPR technology researchers found it to be fundamentally connected to wing coloration. Silencing the gene resulted in patterns remaining the same but all pigmented coloration disappeared, leaving the butterfly wings black and grey.

One of the stranger results noticed when researchers altered the optix gene was the appearance of a blue iridescence in some species. This stark blue that resulted seemed to be related not to an actual pigment, but to a deeper structural coloration resulting from the gene silencing.

A Zebra Swallowtail butterfly feeds in Arnaud Martin’s lab
A Zebra Swallowtail butterfly feeds in Arnaud Martin’s lab

One of the fundamental insights these dual studies reveal is how closely-related species can evolve a hugely diverse variety of effects that are controlled by the activity of single genes.

"Every single experiment has yielded unexpected results, and it's quite a eureka moment to have a new butterfly coming out of its cocoon and revealing the surprising effects of CRISPR," says Martin. "The mutations have had very specific effects."

This recent research seems simple enough, but its simplicity is deceptive. These kinds of studies could not have been achieved just a few short years ago. The breakthrough in CRISPR gene editing now allows scientists to explicitly target genes and identify their effects. This butterfly research demonstrates how single genes can evolve to direct similar functions, but with increasing levels of novelty.

The next big question for this research is to understand how these genes exert their patterning and coloring activity – and can that activity be rewired or customized?

The WntA gene study was published in PNAS, while the Optix gene study was published in PNAS.

Source: George Washington University

View gallery - 17 images
2 comments
Paul Anthony
The study seems to stop at the visual effect of changing the gene. What if there are other effects. For instance the thickness of the wing, or perhaps the surface texture. Perhaps they are not interested in that however it seems like a missed opportunity not to investigate if there are any other changes.
warren52nz
I guess eventually you'll be able to order butterflies that have your face on it or some such. I would be a hit on Valentine's Day.