Gene editing tools like CRISPR are taking the scientific world by storm, promising new cancer cures and superfast breeding of plants and animals.

So a Federal Government decision not to regulate some types of gene editing used in agriculture and medicine may have many researchers breathing a sigh of relief. But what does it all mean?

Key points: Changes will make Australian gene technology regulations more relaxed than New Zealand and Europe but tighter than the US

Changes will make Australian gene technology regulations more relaxed than New Zealand and Europe but tighter than the US Some scientists urge caution and question the arguments used to support deregulation of the most common form of gene editing

Some scientists urge caution and question the arguments used to support deregulation of the most common form of gene editing Food authority yet to decide on safety assessment and labelling of gene-edited foods

To understand the decision, announced earlier this month, we first have to understand a bit more about, well ... mutants.

We're not talking about two-headed beasts here, but less scary-looking mutants that are essential for evolution and humanity's ability to feed itself.

Alterations in DNA — caused spontaneously when cells divide, or because the DNA is affected by something like radiation from the sun — can bring about changes in an organism that are passed on to future generations.

The natural world preferentially selects for genetic variations (or mutations) that are best suited to particular environments — in a case of 'long live the most successful mutant'.

Since the dawn of agriculture, farmers have selectively bred plants and animal varieties that have useful mutations.

And for decades scientists have been deliberately zapping plants with radiation to increase the number of mutant plant varieties available — a process called "mutation breeding".

Fast forward to 2019 and scientists are now using the latest genome modification tool — gene editing (using technologies like CRISPR) — to make selective breeding happen even faster.

Gene editing means scientists can much more precisely target, cut, delete and edit parts of the genome they want to change. So, no more wasting time creating a bunch of useless mutants!

CRISPR is now being applied in plants, animals — and even in humans, with last year's sensational announcement by a Chinese scientist that he had created the first gene-edited human twins.

While most scientists oppose such lines of research, there's a lot of excitement among researchers about using tools like CRISPR in agriculture.

And, just like in the previous GM debate, governments around the world have been divided on how to regulate the new technology.

Last year Chinese geneticist He Jiankui prompted outcry from scientists when he announced he had gene edited human embryos. ( Getty: S.C. Leung/SOPA Images/LightRocket )

The case for deregulation

According to Karinne Ludlow, an expert in biotechnology law at Monash University, most gene-edited plants and animals in the pipeline have no new DNA inserted into them. So there's been a question over whether they would be covered by laws that regulate genetic "modification".

"The argument is: should we treat this type of gene editing more as a type of mutation and therefore not regulate, or treat it as a deliberate modification and therefore regulate?" she said.

Until recently it had been unclear whether Australian gene technology laws would apply to techniques that produce changes that theoretically could occur naturally, or during mutation breeding, which was exempted from the regulations when they first came in.

Dr Ludlow said the lack of legal clarity had made it difficult for researchers wanting to use the technology to engineer useful traits.

But on April 10 the Australian Government decided not to regulate this form of gene editing or what they call SDN-1 (or site-directed nuclease) techniques. Gene editing will not be regulated if it is only used to cut DNA in a specific place and the cell's natural DNA repair process is allowed to operate, without further intervention.

Mushrooms that have been engineered to last longer may be among the first gene edited foods on supermarket shelves in the US. ( Getty: Whitestorm )

The argument is that this kind of gene editing is just a more precise way of producing genetic mutations — and that's something we've been doing for years.

"If these technologies lead to outcomes no different to the processes people have been using for thousands of years, then there is no need to regulate them, because of their safe history of use," the gene technology regulator Raj Bhula told ABC last year.

"If there is no risk case to be made when using these new technologies, in terms of impact on human health and safety for the environment, then there is a case for deregulation."

The decision by the Gene Technology Regulator has been described as being "middle ground" between the more relaxed approach of countries like the US and Brazil, and the tighter regulations of the European Union and New Zealand.

Dr Ludlow said the Australian decision made sense.

"We already accept that humans mutate DNA. We do it all different ways. We apply chemicals, we apply radiation," said Dr Ludlow.

"We know from 80 years of mutation breeding in plants that we don't tend to get dangerous things happening."

Dr Ludlow said more complex forms of gene editing, including those that use a template to direct the repair, or those that introduce foreign DNA into the genome, would still be regulated under the gene technology laws.

... and the case against

But geneticist Jack Heinemann from Canterbury University in New Zealand argues the logic used for deregulation "doesn't stack up".

He said mutation breeding, which uses chemicals or radiation, had a safe history because, even though it was exempt from gene technology regulations, it has been tightly controlled by institutions.

"I can't just go and buy some Cobalt 60 [a source of radiation] and take it home to my garage and mutate my cat," said Professor Heinemann.

By contrast, he said, deregulation of gene editing could see more backyard DIY gene editing with dubious consequences.

In 2017, a biohacker injected himself with CRISPR to try to make himself more muscly. It was a move likely inspired by gene editing research aimed at making super-muscly pigs.

"I'm not sure myself personally whether [SDN 1 gene-editing techniques] should be regulated but I'm sure I wouldn't deregulate them based on the reasoning and logic the Office of the Gene Technology Regulator," said Professor Heinemann.

Professor Heinemann said it was also possible the targeted nature of gene editing may cause changes in genomes that are unlikely to occur in nature.

He said experiments had shown that some areas of genomes are less susceptible to mutations by radiation or chemicals, because of the way the DNA is compacted and protected by proteins and other molecules.

But the way the molecular scissors in gene editing are guided to particular sites on the genome may force changes to these sites, which could otherwise be protected.

And while scientists are currently working to reduce CRISPR's known 'mistake' rate, Professor Heinemann said speedy gene editing could rapidly introduce cumulative unintended changes that, if not easily observed, may not be picked up before an animal or plant was commercialised.

In the case of the CRISPR twins from China, questions have been raised about possible unintended effects of disabling a gene to reduce the twin's risk of HIV infection.

The same gene also helps protect the lungs, liver and brain during some other serious infections and chronic diseases, according to some reports.

CRISPR food on our supermarkets shelves?

The inventor of CRISPR, Jennifer Doudna, has predicted we'll be eating the first gene-edited foods in five years.

The first gene-edited food on supermarket shelves in the US could be non-browning mushrooms, destined to have a longer shelf life.

Other gene-edited developments include flu-resistant pigs, hornless cows that can be safely kept in confined spaces together, crops designed to resist pests, disease, salinity and drought. And then there are spicy tomatoes, peach-flavoured strawberries and even lab-grown meat.

Regardless of whether gene editing dodges regulation under Australia's gene technology laws, the food regulator must also have a say before CRISPR foods go on sale here.

FSANZ is currently reviewing how it will deal with foods developed using gene editing (which they call a "new breeding technology").

Researchers are using gene editing in crops to select for a whole slew of traits ( Getty: Prevor Drake )

Many of the public submissions to the FSANZ review want any food derived using gene editing to be labelled. But Dr Ludlow said it's unlikely that FSANZ will end up requiring special safety assessment of foods produced by the techniques just exempted from the gene technology laws.

"We aim to report back later this year, when we will release our final report on the review, including our recommendations," FSANZ said in a statement.

"Any change to the [Food Standards] Code would involve a proposal process which involves public consultation."

So watch this space.

What about medical applications?

Beyond agriculture, gene editing also promises to revolutionise medical research, helping scientists to do everything from study how genes work to develop cancer treatments and replacement organs.

Cancer researcher Jennifer Byrne of the University of Sydney said most medical research involving gene technology is already heavily regulated and contained.

Still, she said her own university's Institutional Biosafety Committee had told the gene technology regulator they were in favour of regulating gene editing.

Professor Byrne said the move to deregulate would "surprise" some of her colleagues.

"Researchers tend to welcome circumstances where no additional regulation is required but from a broader perspective there may be concerns," she said.