Modifying foods: Past, Present and Future

Humans have been modifying produce for millennia, selecting for genes which boost beneficial traits
11 July 2022

Interview with 

Helen Anne Curry, University of Cambridge & Gideon Henderson, Department for Environment, Food and Rural Affairs


At the end of May, the UK’s Department of Environment and Rural Affairs - DEFRA - announced they were presenting a new bill to parliament to potentially relax laws around the growth and sale of gene-edited foods in the UK. This has implications for the food that ends up on our supermarket shelves, as Julia found out…

Julia - I've just popped to the supermarket to do my weekly shop. I always start off in the fruit and veg aisle, favourite part of the supermarket. I was looking at the fruit and veg in front of me and I wondered, "how much has this produce actually changed over the years?" There's such a vast selection of fruit and veggies in our supermarket, but have they always looked and tasted this way? I asked Helen Anne Curry, a historian of science and technology at the University of Cambridge. I asked her how much influence we've had over the produce that's ended up on our supermarket shelves.

Helen - Humans have clearly been modifying plants knowing that they're changing them over time for many hundreds of years.

Julia - Selective breeding really took hold in the 18th century with agriculturalists like Robert Bakewell separating livestock and intentionally pairing animals together to get offspring with beneficial features before we even knew what genes were. We could see that our parents' traits were passed on to their children and plants were the same.

Helen - In breeding plants to make the appearance of traits more persistent and consistent over multiple generations. And that intensifies in the late 19th century.

Julia - This in breeding is a form of genetic selection; genes which make plants bigger or tastier get passed on as the seeds from those crops are chosen for sewing. So, as I'm walking around the supermarket today, what produce on our shelves has undergone this type of transformation?

Helen - Any crop that you might pick up will have transformed dramatically over time as different individuals, different communities, have become interested in different qualities. Whether it's wild tomatoes or quite tiny fruits, nothing like the plump juicy vine ripened tomatoes that you might get. Berries over time, things like blueberries or blackberries in some cases, have been selected as larger varieties appear in part because of chromosomal changes. So they might be tetraploid or octoploid, meaning they have greater numbers of chromosomes, which can be a process that happens spontaneously, but gets selected for when it happens. And someone sees the larger fruit and takes that.

Julia - This in breeding can increase the yield of beneficial traits in plants, but it can also have its downsides if the majority of produce carry very similar genetic material?

Helen - Hybrid corn in the United States in the 1970s had been bred to incorporate cytoplasmic genetic material from a particular plant that had had a quality that seed producers really wanted. Something like 70% shared this one set of cytoplasmic genetic material and it made them all simultaneously susceptible to a new strain of Southern leaf blight, a fungal pathogen. And there was a collapse of the corn crop that year.

Julia - Diversity within crops is very important. So pretty much all foods in our stores have been selectively bred to harbour genes which produce enhanced traits. This technically is genetic modification, but that's not how we currently define this term.

Helen - The contemporary use of genetically modified often refers to trans genetically modified plants and animals. A transgenic organism is one in which a portion of genetic material from one genome often, potentially from a different species, has been transferred into the genome of an entirely different organism

Julia - In our supermarket, very little food is genetically modified in this way with pieces of foreign DNA inserted into the produce. In the UK, we don't have direct GM foods on the shelves. There are even some labels on foods that claim they're GMO free, but that doesn't mean we don't come across them

Helen - Around the world, a significant number of genetically modified crops are grown. They're chiefly maize or corn, soy, cotton. There are some additional crops as well. For example, genetically modified eggplant and papaya. And so irrespective of what the particular regulations are, it is likely that consumers have come across, in their diets, genetically modified plants, either as primary products in industrial food processing or that they have eaten animals that have consumed genetically modified foods.

Julia - There's a chocolate bar here that says on the back, it has a little asterisk, saying that it contains genetically modified sugar beets and soya beans. Transgenic modification of foods can be done to enhance or add novel characteristics, potentially to our benefit. But the term GM is still in the shadow of bad press from the 1990s, when the British media sparked a tirade against modified produce, describing them as Frankenfoods. Why a proportion of the public sided against GM may have come from their initial use -

Helen - There was a lot of initial pushback around the kinds of traits that were being developed and who they were seen to benefit. One of the main traits that was of interest to seed companies was a trait that made crops resistant to herbicides, which were then sold as a package in which you purchased both the herbicide that the plant didn't respond to as opposed to all the other weeds growing around it and the seed itself.

Julia - When these resistant seeds were released, petrochemical companies were just entering into the seed company space.

Helen - In an instance like that, I think it was very quickly perceived by activists, and by many consumers as well, that new technologies were being put on the market without any obvious benefit to them.

Julia - Given how much food means to us, this modification by big companies sparked worry about what the goal was behind using these technologies and if the companies holding the power to edit our food could be trusted. GM arising in these circumstances means it's not really surprising that the public are wary. As the UK and EU have a de facto ban on the sale and consumption of these goods for humans, our supermarkets here have remained pretty devoid of modified foods. But, in the UK last month, it was announced that a new bill was being presented to parliament, called the Genetic Technology or Precision Breeding bill. This bill states that gene edited food could be grown and sold in the UK. Gene edited food differs from those transgenically modified crops which cause the public uproar in the nineties as Gideon Henderson, the chief scientific advisor at DEFRA, explains.

Gideon - Tools have come along that enable very precise editing within the genetic material of a species. It's what's sometimes called cisgenic in that you're working within the material of a species rather than inserting material from elsewhere. And these genetic editing tools also enable us to make very precise changes, changes that very closely mimic those that you could do by natural breeding, but much more slowly and less precisely.

Julia - Editing the genes of food using biology could essentially do what we've been doing for centuries in selectively breeding beneficial traits in crops, but in a fraction of the time. If this bill is passed, we could be seeing changes to the foods on our supermarket shelves.

Gideon - Perhaps the most immediate change that we might see as consumers in this country is that products that have beneficial qualities for us as humans, or for the way that they're grown,. I think we're going to see new crops developed which will provide significant benefits to the environment and significant benefits to human health through their consumption.


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