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A Hands-On Look At Gene-Editing Technique CRISPR, Which Could Be A Game-Changer For Ag

George Washington University research assistant Chris Day positions a needle to inject CRISPR Cas9 and guide RNA into butterfly eggs.
Amy Mayer
/
Harvest Public Media
George Washington University research assistant Chris Day positions a needle to inject CRISPR Cas9 and guide RNA into butterfly eggs.

In a lab at George Washington University, painted lady butterflies flutter in mesh houses. This is where assistant professor Arnault Martin and his research group use the new gene-editing technique CRISPR to unlock secrets about the colors and spots on the butterflies’ wings.

CRISPR has allowed them to isolate a precise gene that controls wing appearance, and they can shut it off at will.

Harvest Public Media's Amy Mayer gets behind the microscope to test out the gene-editing technique CRISPR.

Butterflies live in a mesh house in the lab where researchers use CRISPR to change their wing patterns.
Credit Amy Mayer / Harvest Public Media
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Harvest Public Media
Butterflies live in a mesh house in the lab where researchers use CRISPR to change their wing patterns.

“What we do with CRISPR is nothing fancy. We don’t do genome editing or detailed surgery, we just break genes,” Martin told a group of visiting science writers in October. 

Martin’s lab explores questions of development and evolution, but CRISPR’s potential extends to new treatments for human diseases, crops engineered to withstand intense rains or long droughts and foods stripped of allergens. The ethical quandaries are also vast, as highlighted recently by a Chinese researcher's claim to have used the technique with human embryos.

Hands-on experience

The other writers and I each got to try the CRISPR technique. We started with a small dish containing a bunch of butterfly eggs on a sticky surface. The eggs were visible to the naked eye as tiny blue-ish dots.

A look through the microscope revealed much more detail, showing they are, in fact, egg-shaped, with one end a bit flatter than the other. We were instructed to nudge them gently with a thin glass rod until they stood on that flat end. It’s harder than it sounds.

When I finally got a few eggs in the right position, I took my dish to a different microscope that was connected to an electric needle full of a reddish fluid. The liquid contained the CRISPR Cas9 protein tool and and something called “guide RNA.”

Researchers compare the gene editing process of CRISPR to a search-and-replace function in a word processor. First, the exact phrase, or genetic location, is identified. Then, it is cut out and other genetic material can be inserted.

“The guide RNA is the specific directional vector that will direct the Cas9 to specific sites in the DNA, to cut there,” graduate student Vincent Ficarrotta explained, adding that the the DNA repairs itself around the cut, and the egg develops normally from that point forward.

Blue and green butterfly eggs are stuck to tape before they are injected with CRISPR.
Credit Amy Mayer / Harvest Public Media
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Harvest Public Media
Blue and green butterfly eggs are stuck to tape before they are injected with CRISPR.

It took some help from one of the research assistants before I managed to align my egg with the needle. When it was in the right place, I tapped a foot pedal and watched through the microscope as red goo oozed into the tiny egg. Experienced scientists can inject a hundred eggs in one sitting. I did barely a few.

CRISPR’s potential

There’s no outcry against this lab’s CRISPR work, which is primarily funded by the National Science Foundation. Compare that to last month, when a Chinese scientist announced at a meeting in Hong Kong that he’d used CRISPR to alter DNA in human embryos to protect a set of twins from AIDS.

Colleagues decried his disregard for the peer review process and questioned the truth of his claim. But scientists and ethicists were left fearing the pending arrival of designer babies, or children genetically altered in utero to suit their parents’ preferences.

Martin said he discusses bioethics and appropriate uses for the technology with his students, encouraging them to “think about several levels of consequences”; for example, how a genetic change will affect future generations of a species.

If used responsibly, Martin said, CRISPR could help solve many challenges, including in agriculture.

A needle is poised to inject butterfly eggs.
Credit Amy Mayer / Harvest Public Media
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Harvest Public Media
A needle is poised to inject butterfly eggs.

“If you want to feed the planet, 9 billion people, I think we will benefit from accelerated domestication from engineering crops so they are less demanding in terms of resources, less vulnerable to pests or less waste, better use of land and so on,” he said.

CRISPR’s use in plant breeding is a bit less controversial than in humans or other animals as seeds can be manipulated so that genetic changes don’t persist into offspring. Agriculture companies already have their eyes on the technique.

“It's a development that we're very excited about,” Bayer Crop Science president Liam Condon said in October, when he was in Des Moines for the World Food Prize.

Companies want the public to understand up front the value of a new technology, he said, echoing what Harvest Public Media reported in 2017.

“One of the issues that we've always had with GMO technology,” Condon said, “is that the benefits are very clear for the grower, for the farmer, but they're not so clear for the consumer.”

He’s confident that CRISPR’s potential to remove food allergens or boost nutritional quality will appeal broadly. What he’s more concerned about is how different governments will approach regulation, as GMOs taught the industry an important lesson after different approval timelines held up overseas deliveries of some U.S. crops.

“It is important that there's kind of a consistent regulatory framework to ensure international trade with whatever is developed using CRISPR Cas 9,” Condon said.

For now, countries are on their own to determine whether new policies are necessary because there is no coordinated effort to establish international regulations. But the flurry of interest sparked by the announcement in Hong Kong may prove the catalyst for a seeking a global consensus sooner rather than later.

Follow Amy on Twitter: @AgAmyinAmes

These butterfly eggs, viewed through a microscope have been injected with the reddish CRISPR solution. The reddish globs are the CRISPR solution.
Credit courtesy Joe Hanly / George Washington University
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George Washington University
These butterfly eggs, viewed through a microscope have been injected with the reddish CRISPR solution. The reddish globs are the CRISPR solution.

Copyright 2018 Harvest Public Media

Amy Mayer is a reporter based in Ames. She covers agriculture and is part of the Harvest Public Media collaboration. Amy worked as an independent producer for many years and also previously had stints as weekend news host and reporter at WFCR in Amherst, Massachusetts and as a reporter and host/producer of a weekly call-in health show at KUAC in Fairbanks, Alaska. Amy’s work has earned awards from SPJ, the Alaska Press Club and the Massachusetts/Rhode Island AP. Her stories have aired on NPR news programs such as Morning Edition, All Things Considered and Weekend Edition and on Only A Game, Marketplace and Living on Earth. She produced the 2011 documentary Peace Corps Voices, which aired in over 160 communities across the country and has written for The New York Times, Boston Globe, Real Simple and other print outlets. Amy served on the board of directors of the Association of Independents in Radio from 2008-2015.