The line between ethically acceptable and unacceptable uses of powerful genome editing technology in human embryos and livestock requires more public conversation and ethical scrutiny, according to the Nuffield Council on Bioethics, following a preliminary review of the technology and how it is being applied currently.
The rise in precise tools to alter DNA, technology known as CRISPR-Cas9, could potentially have a dramatic impact on society, with human reproduction and livestock farming identified as two key areas of concern.
Genome editing raises the possibility of engineering humans with ‘desirable’ genetic traits, which would be inherited by any subsequent offspring. Significant developments in the field include a Chinese experiment in which embryos were edited to correct for an inherited blood disorder, and the approval this year for genome editing research on human embryos in the UK to investigate which genes are essential for embryonic development.
While these are basic research projects, they set off an ethical debate over whether the use of these techniques in human embryos ought to be permitted. Following a three day summit in Washington DC last December, the national academies of China, UK and the US recommended the formation of an international forum to oversee use of the technology, but stopped short of calling for a moratorium on the use of CRISPR-Cas9 in basic research in embryos.
The Nuffield report acknowledges there are ethical arguments in favour of editing the genomes of embryos, such as potentially preventing the inheritance of cystic fibrosis and more than 4,000 other known diseases caused by single gene defects, which are thought to affect around 1 per cent of births worldwide.
But it could open the door to what the report calls “liberal eugenics” where children are modified to suit their parents’ preferences.
There are also fears that changes to an embryo’s DNA could have unknown harmful consequences and also will passed on down the generations.
Gene editing on farms meanwhile, a much closer prospect, could result in faster growing crops, more eggs from chickens, pigs with resistance to swine flu, and hornless cattle that could safely be housed in confined spaces.
Meat, eggs or milk produced in this way might show no traces of the modification, and so fall into a legal grey area. “This is significant because of the differences in the way that GM and non-GM foods are regulated, labelled and perceived by consumers,” the Nuffield report says.
The Council aims to finish its report next year, when it will present conclusions and recommendations. In parallel, the US National Academies of Sciences, Engineering and Medicine is putting together a report early next year on applications of genome editing.
Warning over off-the-shelf home kits
The report also warned that the low cost, ease of use and availability of home-made kits online makes the use of genome editing technologies accessible to amateur, unregulated users, raising concerns that malicious "biohackers" or careless hobbyists might whip up something potentially harmful.
“These may include DIY 'garage' scientists, school and undergraduate students, and others with an interest in biological research and the possibilities - whether potentially beneficial or harmful - raised by genome editing,” the report says.
Kits are available on the internet for as little as £100. The report also found several CRISPR-Cas9 experiments were happening outside established labs, such as by young students in a biology contest called the International Genetically Engineered Machine competition.
Although techniques for genome editing have been developed since the mid-1980s, the methods are difficult to apply and require experienced technicians. What changed in 2012 with the arrival of CRISPR-Cas9 was the ease of making precisely targeted alterations to DNA sequences.
This has prompted widespread uptake of the technology, which “requires skills that can readily be acquired by those with standard degree level skills in molecular biology,” the report says.
Potential applications abound. Genome editing could help researchers eradicate the mosquito species that transmit malaria and the Zika virus.
A more speculative use of genome editing, according to the report, would allow biologists to resurrect extinct species, such as the passenger pigeon.