Gene genius
But scientific advances face uphill battle for legal and public approval
THE small town of Albany, Indiana, was recently thrust into the headlines as the biotechnology company AquaBounty began farming genetically modified (GM) salmon at its nearby aquaculture facility.This came after a decades long battle to gain regulatory clearance in the US.
The company created a line of GM salmon in 1989 using recombinant DNA technology.Two genes – a growth hormone gene from the Chinook salmon and a promoter gene from the ocean pout – were inserted into the genome of Atlantic salmon.
The resulting ‘AquAdvantage’ salmon can grow to market size twice as quickly as non-GM Atlantic salmon farmed under the same conditions, and requires 25 per cent less feed in the process.
This form of genetic modification, in which genes from one or more organisms are inserted into the genome of another organism to produce novel traits, is referred to as transgenesis.
In November 2015, the Food and Drug Administration (FDA) approved AquAdvantage salmon for human consumption in the US. It is the first and only GM animal to have gained that accreditation.
However, it wasn’t until March 2019 that the FDA lifted an import ban preventing AquAdvantage salmon eggs (produced in Canada) from entering the US.
This cleared the way for production to begin in Albany and the company expects a first harvest in late 2020.
It is anticipated that the facility will produce 1,200 tonnes of fish annually once operating at full capacity.
In April 2019, AquaBounty received approval from Environment and Climate Change Canada to also grow fish at its Rollo Bay facility on Prince Edward Island.
AquAdvantage salmon has been sold to consumers in Canada for several years, having been farmed in Panama to date.
As AquaBounty fought for regulatory approval of its transgenic salmon in North America, a revolutionary new technique for genetic modification, called CRISPR-Cas9, has made waves in the scientific community.
CRISPR-Cas9 is a naturally occurring gene editing system, first detect
ed within the genomes of bacteria.
The system has two key components that work in tandem to produce mutations in DNA: the Cas9 enzyme, sometimes described as a pair of ‘molecular scissors’ that cuts through DNA to allow ‘edits’ (for example, the addition or removal of genetic material); and guide RNA, which binds to the targeted DNA to ensure that Cas9 cuts in the right location.
Together, these molecules form one of the most rapid and accurate tools for genetic modification currently available to researchers.
CRISPR-Cas9 has many potential applications in the aquaculture industry.
Researchers have used the system to create organisms with traits such as increased size, pathogen resistance and sterility; the latter viewed as particularly desirable in GMOs to prevent ‘contamination’ of wild organisms if they escape into the natural environment.
In Japan, CRISPR-Cas9 has been used by scientists to create a more muscular version of a highly prized fish species, the red seabream.
The myostatin gene, known to restrict muscle development, was knocked out and resultant GM seabream were found to possess 16 per cent more skeletal muscle than the non-GM organism.
A landmark ruling handed down by the top court in Europe, the European Court of Justice, in 2018 made gene edited organisms created with technologies such as CRISPR-Cas9 subject to the same controls as other GM organisms.
Whether these gene edited organisms will also be subject to lengthy regulatory review in the US comparable to that required of AquaBounty’s transgenic salmon remains to be seen.
In mid-June 2019, President Trump signed an executive order instructing federal agencies to streamline the regulation of GM crops and other organisms.
“A survey of US adults found over 90 per cent of respondents felt some level of opposition to GM foods”
The commercial success of products such as the AquAdvantage salmon will ultimately be determined by the willingness of consumers to embrace GM technology.
Techniques for genetic modification present a key avenue of opportunity for improving traits in farmed stocks such as growth rate, nutritional content, resource use efficiency, and resistance to environmental stress and pathogens.
But the safety and ethical implications of GM crops in the agricultural industry have been a subject of contentious debate for decades.
A survey of US adults recently published in Nature Human Behaviour (2019) found that more than 90 per cent of respondents felt ‘some level of opposition’ to GM foods.
Interestingly, there may be a particularly strong antipathy towards GM animal products.This is seen in a separate survey (Thomson Reuters, 2010), in which 60 per cent of respondents were willing to consume GM plants, but GM meat and fish products were acceptable to just 38 per cent and 35 per cent respectively.
A variety of concerns have been raised about the environmental risks posed by GM organisms.
These include the increased use of pesticides and herbicides on GM organisms designed to be resistant, the escape of GM organisms into the natural environment where they may genetically ‘contaminate’ or out-compete non-GM organisms, and the potential impact of GM organisms on biodiversity.
Concern about the safety of GM foods for human consumption (for instance, unintended effects on allergenicity and toxicity) is also widespread.
The Pew Research Centre (2018) reported that 49 per cent of US adults believe that ‘foods containing GM ingredients are worse for one’s health’ than those that do not.
Only time will tell how effectively AquaBounty and other proponents of GM technology can respond to such concerns in the court of public opinion.
But if their dogged pursuit of regulatory approval over the last three decades is any indication, it’s a safe bet that they won’t shy away from the challenge.