In a recent consultation on the regulation of genetically modified organisms (GMOs) produced by genome editing (GE) or other genetic technologies, DEFRA* made a distinction between genetic changes that could have been developed using traditional breeding methods and those that could not. However, the use of traditional breeding methods as a benchmark for what is and what is not acceptable is neither useful, nor scientifically logical.
Firstly, it is worth remembering that traditional breeding methods are not equivalent to unassisted or natural breeding methods. They comprise a number of techniques not possible without human intervention, such as artificial insemination (AI), superovulation, in vitro fertilisation (IVF), and caesareans. For this reason, traditional breeding methods can lead to genetic changes that would not have been possible unassisted, such as the disproportionate amount of breast muscle achieved using AI in modern turkey breeds, resulting in them being unable to reproduce naturally.
Secondly, even when entirely natural breeding methods are employed, artificial selection by humans can produce animals with severely reduced welfare. An example of this are brachycephalic (flat faced) companion animals (mainly dogs, cats, and rabbits). The flattened shape of the skull gives rise to breathing difficulties in many of these breeds, causing chronic discomfort and respiratory distress. Dog breeds such as pugs and French bulldogs are a result of traditional breeding methods, and these are still being bred despite current UK legislation banning the breeding of dogs that promotes inherent health and welfare-reducing traits (legislation.gov.uk). You can read more about the welfare problems of brachycephalic dogs alongside many other issues created by traditional breeding in our web resource on Genetic Welfare Issues of Companion Animals. If GE techniques were used to create such extreme phenotypes with compromised welfare, legislation should clearly be in place to prevent this. That extreme breeds are still being bred highlights not only the need to regulate but also to enforce existing legislation on phenotypic animal characteristics and health, no matter how the genotype was produced.
And thirdly, some genetic changes are difficult to introduce with traditional breeding methods. An example of a genetic trait with a positive effect for the welfare of some ruminant livestock species is the polled gene. This gene leads to dehorned calves and goat kids, preventing the need for disbudding, which is the removal of the horn buds at a young age. Use of anaesthetic is compulsory in the UK for this painful procedure, but this is not always used elsewhere, and even with anaesthesia disbudding may cause pain after the procedure. Polled (hornless) offspring is achievable using GE techniques, but current legislation would label these animals as GMO, effectively preventing them from entering the human food chain in Europe. Although a previous attempt to introduce this gene into cattle was associated with some unwanted genomic changes (technologyreview.com), this should not provoke a knee-jerk reaction leading to the techniques being abandoned. Instead, it emphasises the need for stringent protocols and testing of all GE applied to animals, in a manner similar to the careful, staged testing process associated with the approval of new drugs.
UFAW sees this as an opportunity for the UK to re-define the regulation of animal GE technology to live up to the notion that emphasis should be on the outcome (preventing welfare reducing traits and phenotypes) and not the method used. In other words, no matter how an animal came to be in possession of certain genetic traits, if these affect its welfare directly, this should be regulated so that – all other things being equal – welfare improving traits are allowed, whereas traits detrimental to the welfare of an animal are prohibited. Not all changes are equal and – especially in terms of animal welfare – there is a need to evaluate the harm as well as the benefit of any GE made, including promoting those that would reduce animal suffering, prevent disease, or improve resilience.
* UK Department for Environment, Food and Rural Affairs
