By Michael Barker
A new gene-editing technique is taking the scientific community by storm – and could have widespread ramifications for the poultry sector.
What if you could create a disease-free turkey, pre-select the sex of chicken or eliminate all traces of salmonella from eggs? It might sound like the stuff of science fiction, but thanks to a game-changing breakthrough known as CRISPR such radical concepts are on the verge of becoming a reality.
CRISPR (pronounced “crisper”) is a technique for editing genes in living organisms, based on an enzyme system called Cas9 that occurs naturally in bacteria and any living organism. By activating it, scientists are able to cut snippets of the DNA chain and essentially edit the animal or organism for the purposes of changing the way it grows, repairing genetic defects and tackling issues such as disease.
Put in simple terms, CRISPR are molecular scissors that can be used to precisely cut DNA. It means that scientists can accurately edit the genome – the DNA – of a chicken, for example. “Imagine the genome of a chicken as a very large book. We can use CRISPR to change a word or letter in that book,” says Mike McGrew, group leader at the Roslin Institute, University of Edinburgh. “What if we could change a few basepairs (a few letters of a word) of DNA in a chicken and it would no longer be infected by or spread avian influenza? That is one of the potential applications that we find exciting.”
The technology is not yet widely available, but it is cheap and fast to develop and with every major genetics company and governments such as those of India and China investing significantly, its widespread use looks inevitable.
Developments are moving rapidly, and David Del Pino, an agricultural engineer who is founder and managing partner of marketing, science and technology platform Freshtrategy, believes it could have a transformative effect on the world’s food supply. “Faced with a dystopian future of famines and wars over the control of food, these organisations have opened up their technology to all those who can make a contribution to the most laudable goal there is: to feed humanity,” he says. “In short, the first stone has been laid for prosperity and world harmony.”
Certainly, the potential applications across the agriculture sector are huge, according to Frédéric Fagnoul, director of research and development at Hubbard Breeders. He cites a list of actual and potential applications including cows without horns, dogs with muscle hypertrophy, mushrooms with less oxidation after slicing, as well as influencing the colour of koi carp and the sterility of GMO salmon.
For the poultry industry, a genetic tool that enables precise and predetermined changes to the DNA genome opens up myriad possibilities for breeders. “Genetic gain through traditional breeding is limited to the genetic variation within the given population of birds,” explains Professor Bruce Whitelaw, Genus chair of animal biotechnology at The Roslin Institute. “The breeder can use CRISPR to introduce desirable genetic variation into poultry flocks that is not already present in a given population. Thus it allows access to genetics not otherwise useable. In this way CRISPR is very powerful, in theory allowing the breeder to use whatever genetic information they want to.”
Whitelaw stresses that CRISPR will not replace traditional breeding – the technology is complementary and simply gives the breeder more genetic variation to select from. While it has yet to be used in production flocks, he says there is considerable academic research exploring how to use CRISPR to advance poultry breeding. The technology could produce disease-resistant birds, for example, mirroring a breakthrough that has already been achieved in pigs through producing animals resistant to blue-ear disease PRRSV. Poultry projects are already exploring if the same can be done for Newcastle disease, Marek’s disease and avian influenza, and that is just the tip of the iceberg.
On a broiler level, Fagnoul summarises the benefits as raised technical performance through improved growth and digestibility, increased disease resistance and immunity, nutritional perks such as a better protein profile or reduced-fat in chicken meat and even animal welfare improvements thanks to in-ovo sexing.
Practical and affordable, CRISPR looks more and more like a silver bullet, but as with any new technology, there are still hurdles to overcome. Fagnoul points out that unlike current GMOs, the trace of genetic modification using CRISPR cannot be detected, raising regulatory question marks over how rules are implemented worldwide, particularly in wildly variable markets such as the EU, USA and China. Biohacking could be a potential threat, while consumer acceptance of human and animal eugenics is always likely to be a challenge.
Critics have warned that the technology is moving too fast and could ultimately lead to such morally questionable outcomes as so-called ‘designer’ babies. Indeed for some, creating animals to suit human needs also has a little too much of the Dr Moreau about it.
The technology is still in its infancy, and issues around intellectual property have yet to be ironed out, but its advocates insist the right frameworks will be in place to deal with such concerns. “The regulatory world is fully engaged with establishing robust and appropriate pathways for product commercialisation,” says Whitelaw, though he stresses that as of today these remain to be put in place and tested.
McGrew acknowledges that as ever with any technology that involves radical new science, there will be a public relations battle to be won. “The regulation of CRISPR-edited animals and plants is unclear and the future public acceptance of CRISPR-modified poultry is also unclear,” he admits “Uncertainty over these issues will hamper uptake of these new tools by the poultry sector… until an open and fair regulatory mechanism is put in place.”
But he adds: “I believe that poultry which have a higher welfare through gene editing, for example by increased immunity to any of the major chicken pathogens, will gain consumer acceptance.”
Overwhelmingly, the feeling coming from the scientific community is one of excitement. Aidan Connolly, chief innovation officer at Alltech, is in no doubt that CRISPR is a game-changer, and any countries or industries that do not get on board from the start will get left behind. “I believe that CRISPR will herald the end of GMOs as we know them and I perceive that it presents an extraordinary opportunity for agriculture,” he states. “Of course, whenever new technology arrives there are always concerns and debates over what it will mean, but I don’t think it will be possible for the farming industry to be competitive in the future if it does not embrace this technology, particularly when it’s clear that those in other countries will.”
The Broad Institute of MIT and Harvard answers some key questions about CRISPR.
Q: What is CRISPR?
A: CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats, which form the basis for CRISPR-Cas9 genome-editing technology.
Q: What does that mean in reality?
CRISPR allows researchers to edit DNA in precise locations, allowing them to permanently modify genes in living cells and organisms for various benefits, such as treating genetic diseases.
Q: Where does CRISPR come from?
A: CRISPRs were first discovered by Francisco Mojica, a scientist at the University of Alicante in Spain, who proposed they serve as part of the bacterial immune system, defending against invading viruses.
Q: What makes CRISPR-Cas9 different from other gene-editing tools?
A: Cas9 is proving an efficient and customisable alternative to other existing tools. Since the Cas9 system is capable of cutting DNA strands, CRISPRs do not need to be paired with separate cleaving enzymes as other tools do. Cas9 can also be used to target multiple genes simultaneously.
Protecting the future of poultry
Mike McGrew, group leader at The Roslin Institute, has led an initiative to develop bio-banks – or frozen aviaries – using germ cells to manage and conserve both rare and industrial breeds of poultry.
The £14 million project was driven by the fact that traditional methods used for species cryopreservation using semen and eggs are either inefficient or impossible in birds.
And CRISPR technology has the potential to give further impetus to the project. “We are using CRISPR tools to edit the genome of chicken now,” he explains. “We produced a chicken with no reproductive cells. We hope to use this chicken to develop a way to freeze down (cryopreserve) chicken breeds, something that is currently impossible. At this point, we are using these tools in research, to understand what genes are important for susceptibility or resistance to poultry diseases.”
A brave new world for agriculture
CRISPR technology has wide implications across the spectrum of the farming sector.
“From the perspective of the wider agricultural field, CRISPR will disrupt all aspects of our business,” says Aidan Connolly, chief innovation officer at Alltech.
“It is clearly a technology that is capable of being much faster, cheaper and perceived as natural by the consumer offers huge benefits in crop production systems, in terms of a wide variety of other animals – fish, pigs and cattle already are part of the group examining what might be possible.”
One innovation that has already made the headlines was a breakthrough by Chinese scientists, who have created pigs with 24 per cent less body fat than normal. It has been suggested that they would be cheaper for farmers to raise and would suffer less in winter because they could better regulate their body temperature.
