Interview with FAO Animal Genetic Resources Group's senior officer
Dr Keith Hammond is the senior officer in FAO's Animal Genetic Resources Group, which has taken the lead role in developing the Global Strategy for the Management of Farm Animal Genetic Resources, to assist countries to better manage the use, development and conservation of their domestic animal diversity. In the interview below, Dr Hammond discusses the scientific background and conclusions of the FAO/Istituto Sperimentale per la Zootecnia workshop held in Rome from 26 to 28 November 1997, of which he was one of the principal organizers and participants.
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Dr Keith Hammond
When semen and an egg come together to make an embryo and that embryo starts growing, and cells differentiate into different tissues such as eyes, liver, ears, skin, etc. resulting in a complete animal, that differentiation actually turns off the vast majority of the 100 000 or so genes in each cell. They quiesce, they go to sleep and only those genes responsible for the specific tissue are switched on. It was not possible to switch these genes on again and render the cell totipotent or embryonic. Only recently have they determined how to switch all the genes back on again. Once they are all switched on again, these somatic or body cells have then regained the potential to develop into a new animal if the nucleus of the cell is injected into an egg which will develop to an embryo and to a live animal. So reversible DNA quiescence is reversing that quiescent process in the animal's DNA. For a long time it was thought that it was biologically impossible.
What sort of process is it?
The meeting did not talk about the technical process, but recognized that the technology has worked, albeit at low efficiency at present, and assumed it will be improved in the future. There are apparently one or two processes that are being patented. But the important thing is that it's achievable. Once all those genes can be woken up again, then you can use virtually any cell of the body in research to ask questions about physiological aspects of development, and you can produce new animals. Only the last process of developing a new animal after taking the cells out of the freezer, is the cloning aspect. The cloning is only necessary at some future time and when you want to reuse whatever you've stored.
How important is this breakthrough in biotechnology for genetic conservation purposes?
For some countries, it could make the difference between taking no action on breeds currently being eroded and conserving these without further delay, particularly where serious difficulties are experienced using currently available in vivo and in vitro conservation techniques.
How soon could these techniques be put to use in developing countries?
For genetic resources at high risk, for some animal species, and where the current live animal and cryo-conservation techniques are not feasible, the expert group considered that countries could begin now with the conservation of cells from skin samples. Conserving cells means conserving the genomes of a breed and making an insurance for the future. This part of the programme, i.e. taking and conserving samples, could be initiated by developing countries immediately. The technologies for re-establishing animals from cells are hi-tech processes and still need considerable improvement in efficiency and cost-effectiveness. Because of the scope of commercial applications, these developments are expected to occur in the coming years. So it is banking on the future.
How do these new cell biotechnologies differ from the current conservation techniques?
When it is possible, it sometimes takes months to get sufficient semen or embryos from enough male or female animals of a breed to put down as storage. For horses, for instance, it can mean working in the field for six months. In contrast, skin samples from the required number of animals could be taken in only a few days, transported to a laboratory and the cells multiplied and frozen. Transport of the samples is easy. The cell culture to multiply the cells and the freezing of the cells require little equipment and could be done, according to the experts, with little training also in developing countries. But there's always a downside - reuse, as mentioned before, is far more complicated. Costly and considerable research is still required.
This opportunity is not a replacement of other conservation techniques and the experts emphasized this. This technology is an alternative in cases where the other techniques are not feasible or reliable, as in many developing countries. Of course, when reuse alone is considered, the very best form of conservation is conserving live animals because when you want to reuse them, their future generations are there ready. But developing countries can't afford to conserve breeds of animals that might be unique but that farmers aren't interested in at this point in time. So, these new cell biotechnologies are broadening the possibilities for the cost-effective conservation of animal genetic resources. They are not replacing other methods.
Did the workshop take a new approach to this debate?
The success we had with this group of experts was that we teased the whole problem apart. We said: "Think about field sampling and collection, transport, temporary and long-term storage, reuse and replenishing the stored material - think about them as operations, in an admittedly connected chain. Can we make an input anywhere?" Rather than just saying, "Oh no, somatic cloning is still very difficult, it can't be used to help overcome animal conservation problems". In effect we can do it up to the final stage of reuse where, right at the moment, we still have a problem.
What are the constraints to the use of these techniques for conservation purposes?
There are constraints - and careful planning, technical competence and some training are still important. Although these new cell biotechnologies are simpler in the field - the samples are quicker and easier to collect, and less delicate to transport, often from remote sites to the central facility - they still require cryotechnology for long-term storage. Also, reuse of the stored material via generation of animals from the cells is currently at the research stage, being further developed. Immediate trials are necessary to demonstrate clearly the value of these new techniques for all mammalian and avian farm animal species, and to refine the field protocols for their use.
Nevertheless, these new cell biotechnologies are broadening the possibilities for the cost-effective conservation of the many animal genetic resources at risk.
18 December 1997
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