Helen Sang - Counting your GM chickens

Kat - Every year roughly ten chickens are raised for every human on the planet, and these birds are a vital source of protein, not just for eggs but their meat too. Mmmm, wings... But avian flu - or bird flu - is a big problem in many regions, putting chickens, farmers, and the wider population at serious risk. Helen Sang, from the Roslin Institute in Edinburgh, has dedicated her career to developing genetically modified chickens, with the hope that they can be made resistant to avian flu.

Helen - So, we're really interested in disease resistance. So, there are all these billions of chickens and because we keep so many of them, there are a number of diseases that can wipe them out and one of those diseases is avian influenza or bird flu. I've been working for some years now with Lawrence Tiley at Cambridge University to try and generate genetically modified chickens that are resistant to bird flu.

Kat - How are you doing with that because obviously, bird flu doesn't affect just chickens? It's a serious problem in humans too, so it's very big concern.

Helen - Yes, it's a big concern and that's one of the reasons that it's our prime target - is that bird flu gives rise to human flu and causes a human pandemic. So, not only is it a real problem to the chickens who get sick and die, to the farmers who produce them because it causes huge losses, but it is also a potential source of human pandemic flu. So, if we could work out a way of genetically modifying chickens so they're resistant to bird flu, I think it would be really seriously considered as an application of GM in commercial chickens.

Kat - Tell me about how you go about that. How do you make a chicken that either can't get the flu or can't pass it on?

Helen - So, this is where Lawrence comes in because he has a lot of bright ideas because he's a virologist. He works on influenza virus. So, he's developing ways that you can express very small molecules in the chicken that will block the replication of the flu virus. So, when a chicken is infected by flu, it can't copy itself and shed more virus, which would infect more chickens or infect people. So, that's our aim - is to find neat ways where we can generate small molecules in the chicken that will be there when the chicken is infected with flu and will block the infection.

Kat - How is that work coming along so far?

Helen - Well, we've had some success. Our first work which was published a few years ago, we expressed a small molecule which seems to stop not the chickens getting infected -they do get infected - but it seems to stop them passing the flu virus on. We're now trying out sort of elaborations on that thing to see if we can make that response stronger so that the birds don't succumb to infection at all. We also want to understand more about the original experiments, why those birds don't pass on the disease.

Kat - We hear a lot about GM crops. Some people are very concerned about eating foods that may have been altered with GM technology. Do you think there's a big challenge if you say, "Okay, this is a genetically modified chicken." People might go, "Woah! No, I am not interested in eating that."

Helen - Yes, I think it's the response of some people but I give a lot of talks and we have an open day here at the Roslin Institute every year where we specifically talk about and present this. I think that if you give people a chance to understand why you're doing the experiments and what it is that you're doing, they can make up their own minds of whether they think it's of value or not. When I give talks, I quite often ask towards the end, "Would you eat a genetically modified chicken that was resistant bird flu?" if there was bird flu in this country - because you don't need it if you're not threatened by the disease. I usually get more than half of the audience - will say that they would consider this. So, I think if people have the opportunity to understand what you're doing and why you're doing it then they will make up their own minds rather than just seeing it as a blanket, "GM is bad. I won't have anything to do with it."

Kat - The techniques that you've been using to make chickens resistant to bird flu, they've involved adding genes in, adding molecules into the chickens. Tell me about some of the other approaches that you're trying.

Helen - So, there is a whole new technology coming along called genome editing where you can make very small changes to the genes in the chicken. So, you're not adding anything new and you can tweak the genes in the chicken to give them different characteristics. This is very new technology. So, we know it's likely that maybe one breed of chickens will be - not bird flu I don't think, but with some other diseases that affect chickens only, not humans as well - that they may have a copy of the gene that makes them resistant to infection with that disease. But commercial chickens don't have that copy of that gene. They have a different version and they're still susceptible to the disease. So, we're hoping that these new genome editing technologies will allow us to change the gene in the commercial chickens so that it's the resistant form that we've identified somewhere else. So, it allows us to move versions of genes around between different breeds of chickens without crossing lots of breeds together and losing the good characteristics that we want to keep.

Kat - What do you think the chicken of the future is going to be like? How have chickens changed over the past 50 years and what do you think the chicken will be like in the years to come?

Helen - Yes, the chicken has changed hugely in the last 50 years. But it's a very gradual change. The poultry breeding makes small changes and when you add them up over the years, it turns out it's a big change. The chicken of the future will maybe be more resistant to a lot of different diseases. I think that's going to be one of the big targets. 

One of the things I'm interested in as well is, can we add in a new gene to the chicken that expresses enzymes that will breakup 'undigestible' feed. So, a lot of food that chickens eat are wheat and maize which are very valuable grains and that is an expense and competes with humans for those grains. But then there's a lot of waste in production of those grains which the chicken can't digest. If we could add in new enzymes into the chicken gut so they can breakdown these materials to release the energy components of those plant materials then maybe chickens will be able to eat lower quality foods and not be so expensive in terms of using high quality grains.

Kat - That was Helen Sang, from the Roslin Institute.