27 Jan 2018

CRISPR crops: the rise of gene edited foods

From This Way Up, 12:15 pm on 27 January 2018

People all over the world are exploring how the gene editing tool CRISPR-Cas9 can be applied in areas like health, pest management and conservation, and in food production. With the Royal Society soon to release a discussion paper on the use of gene editing in agriculture, Simon Morton explores how this genetic technique's already being used to produce food in the US, and how it could be used here in New Zealand.

DNA double helix through an electron microscope

DNA double helix through an electron microscope Photo: (Flickr user Karl-Ludwig Poggemann CC BY 2.0)

There's a revolution going on in the world of genetics; it's called CRISPR gene editing, so how is this genetic technology being used to breed and grow the plants and animals that we eat, and how is it being regulated both here and overseas? 

Before having a go at explaining what gene editing is (great explainer from The Royal Society), I thought I'd lay my genetic credentials on the table. I've been discussing genes and genetics for over 10 years now as a journalist - everything from sequencing the genes of beer yeast to gene therapies that restore hearing.

I love biology and genetics seemed like a good way to explain the physical world around me. But I soon realised I knew nothing about how DNA actually works: how does this invisible molecule that's in nearly every living cell make me me, you you, a cat a cat, and a poodle a dog? How can 4 letters, the chemical sequences of  A C T G really be the foundation of all life on this planet?

I started stalking my local genetics lecturer, and before long was crashing biomedical degree courses at a nearby university to learn about evolution, how DNA works and about population genetics. I was allowed to work in a lab discovering how to use pipettes, fill gel baths and wear a lab coat; all part of a project to classify octopuses caught in and around New Zealand and establish how they were related. I even got my name on a yet-to-be-published scientific paper with the snappy title of 'Systematic and phylogeny of New Zealand benthic octopuses (Cephalopoda: Octopodoidea)'.

When CRISPR first hit the headlines a few years ago it sounded like magic. It raised the prospect that we can precisely turn genes on and off at will. Before CRISPR there were other ways to edit a genome, but CRISPR is relatively cheap and easy to do, with DIY CRISPR kits now available online in the US.

This approach differs from more traditional genetic modification where genes are spliced from one species to another; after all, who wants a frog gene in their tomato!? But I realised CRISPR can also be used to genetically modify an organism and mix genes from different species, creating what's known as a GMO or genetically modified organism.

So is CRISPR really just another tool that we should embrace or do we need to slow down and assess the consequences of this new technology?

For starters, CRISPR isn't all that new: it's a biological system that's been used by bacteria for billions of years. It's part of a bacteria's immune system and allows them to remember, recognise and then get rid of viral infections. Simply put, when a bacteria is attacked by a virus, it identifies it as an enemy, cuts some of its DNA out, and then kills it. This snippet of DNA, a genetic mugshot if you like, is stored in a library, so that next time the bacteria comes across the villainous virus, it does a quick search of the mugshot library, recognises it as an enemy, and zaps it.

It's this ability to recognise a sequence of DNA on a genome, and then precisely target it that forms the basis of the CRISPR- Cas9 gene editing system and scientists are using it to fight diseases and develop new drugs, control pests and grow food, and it's crop production that we explore in this programme.

Scientists and the food industry are intrigued by CRISPR's potential application to food production, thinking it could be used to boost yields, develop drought and disease resistant crops, and cut food waste by increasing shelf stability. That was the aim of a mushroom that doesn't turn brown when you keep it in the fridge, approved by US regulators to become the first gene edited food to go on sale to the public. The US authorities said these mushrooms could be grown commercially as no genetic material was added, so technically they hadn't been genetically modified and were not considered to be a GMO. 

With more than 30 gene edited crops in the process of being tested, and China also heavily committed to the technology, there are many more examples in the pipeline. Some of the examples cited by the selection of crop scientists I interviewed for the show include disease-resistant cassava that can flower more easily, gluten free wheat, and low-GI potatoes; better for diabetics and with the added bonus that they don't produce so much of the carcinogen acrylamide when they are fried or cooked at high temperatures.

Meanwhile growing CRISPR gene edited foods for sale here in New Zealand is heavily regulated under the Hazardous Substances and New Organisms Act 1996 (also known as HSNO). But doing so is far easier overseas. So how will New Zealand regulate these foods from coming here? How can we police our borders for CRISPR foods when the genetic changes that are made are the same in many cases as those that happen in nature? And how will gene edited crops produced overseas impact on our key exports?

The CRISPR system for editing genes is evolving at a rapid pace, and scientists and food producers will find explaining the intricacies and the need for this work to a sometimes distrustful public a real challenge.   

More from RNZ on gene editing and CRISPR.

This programme was produced with support from the Aotearoa New Zealand Science Journalism Fund.

Sound engineers: Steve Burridge and Marc Chesterman
Music: Bevan Smith