What is gene editing, and is it a force for good?

EARLIER this year the Genetic Technology (Precision Breeding) Act 2023 came into force in the UK. Its purpose was to establish the legal conditions to enable the sale of plant and animal products in the UK that have been subject to genetic changes. It also set parameters for risk assessments and marketing.

Gene technology has been controversial in the UK since the Daily Mail first started campaigning on “Frankenfoods” in the mid-1990s. But what is gene technology – why is it controversial – and what’s the difference between gene editing and gene modification?

Put simply, genetic engineering is the deliberate manipulation of an organism’s genetic material to modify its characteristics. It’s already being used to alter crops so that they’re resistant to pests, diseases, and extreme weather conditions.

There is concern that unintended environmental and social consequences may result from genetic manipulation. Resistance may disrupt the fragile natural balance of ecology, particularly through inter-breeding, and where gene technologies are subject to private patents an already corporate-heavy food system may become even more centralised.

Gene technology also allows governments and food businesses to pursue greater yields without necessarily addressing environmental challenges, thereby supporting a policy perspective that prioritises the doubling of food production by 2050. This potentially undermines efforts to urgently reform food systems so that they regenerate rather degrade ecological security, reduce waste, improve nutrition and support farmers by empowering more localised supply chains.

Genetic modification
Historically, much of the public concern around gene technology has centred on genetic modification (GM), which involves introducing foreign genes or genetic material from one organism into the genome of another organism.

Genetic modification can be imprecise because it may involve introducing multiple genes or changing the organism’s genetic makeup more extensively.

Gene editing
Gene editing is much more precise and focusses on altering specific genes within an organism’s existing genome. It typically employs tools like CRISPR-Cas9 to make targeted changes to the DNA sequence, such as deleting, replacing, or inserting specific genes.

It has been argued that gene editing is a molecular version of the selective breeding that’s taken place on farms and in gardens for centuries.

Unlike GM, gene editing allows for the modification of a single gene or a few genes without affecting the rest of the genome.

Writing for The Conversation, Gavin Bowen-Metcalf, a lecturer in Biomedical Sciences at Anglia Ruskin University says, “Our DNA is made of four key molecules called bases (A, T, C and G). Sequences of these four bases are grouped into genes. These genes act as the ‘code’ for key substances the body should make, such as proteins.

“Gene editing is a technology that can change DNA sequences at one or more points in the strand. Scientists can remove or change a single base or insert a new gene altogether. Gene editing can literally rewrite DNA.

He says “There are different ways to edit genes, but the most popular technique uses a technology called CRISPR-Cas9, first documented in a pioneering paper published in 2012. Cas9 is an enzyme that acts like a pair of scissors that can cut DNA.

“Depending upon what the scientist wants to achieve, they can just remove a segment of the DNA, introduce a single base change (for example changing an A to a G), or insert a larger sequence (such as a new gene). Once the scientist is finished, the natural DNA repair processes take over and glue the cuts back together.

“The benefits of gene editing to humanity could be significant. For example, making a single base change in people’s DNA could be a future treatment for sickle cell disease, a genetic blood disease.”

Bowen-Metcalf recognises that gene-editing comes with risk and that “Unless governments work together with scientists to regulate its use, it could become another technology that benefits only the wealthiest people.” However, he says that laws and regulations surrounding this technology are strict and that gene editing “holds the potential to cure genetic disease and create crops resistant to drought.”

Friends of the Earth urges a more cautious approach. They say that “Studies show that, far from being ‘precise’, gene editing can cause genetic errors, even if only a genetic ‘tweak’ is intended. Genes can be changed at additional locations and gene editing can interfere with gene regulation.”

They point out that common gene editing objectives, such as hornless cows and disease resistance, could be used to facilitate the poor animal management, such as over-crowding and the continued use of indoor, high energy and feed-reliant Concentrated Animal Feeding Operations (CAFOs).

Friends of the Earth is also concerned that gene editing could drive a specific trait through “a herd or population of farm animals that could accidentally spread to the natural population, potentially affecting biodiversity and even an entire ecosystem.”

In a sign that attitudes to gene editing may be becoming more nuanced, Peter Stevenson, policy director at Compassion in World Farming, recently recognised that in certain circumstances gene editing could be beneficial.

In 2022, scientists genetically engineered a hen that lays eggs from which only female chicks hatch. In response Mr Stevenson said, “Compassion is usually extremely wary of gene editing but believes that in this exceptional case it is justified in potentially helping to prevent the killing of millions of day-old male chicks. Neither the chicks nor the eggs are gene edited. It is only the hens that produce the female-only chicks that are gene edited. Compassion has given in-principle support to this development as it could lead to the end of the killing of male chicks.”


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