The present situation
The case against institutionalized preservation
The case for preservation
Future needs
Proposal
Conclusion
Bibliography
J. Hodges
Dr John Hodges was formerly Senior Officer, Animal Genetic Resources Group, FAO and, previous to that, professor of animal genetics at the University of British Columbia, Vancouver. He is now a consultant and his address is Weissenstein 8, A-5730 Mittersill, Austria.
Since 1946, one year after FAO came into being, national-level projects on animal production and genetic resources have been a constituent part of the Organization's programme for the improvement of livestock in developing countries. More attention has been focused on the regional and global levels in recent years, in view of the increasing international movement of livestock, semen and embryos. Few countries are now solely dependent on their indigenous animals and all countries have an interest in the world's common heritage of domestic breeds and species. The Committee on Agriculture (COAG), one of FAO's governing bodies, reviewed the entire livestock programme in 1989 and endorsed the technical aspects of its utilization and conservation work as well as the basic philosophy underlying these activities. It recommended an urgent expansion of the programme to meet the increasing needs and requests of governments of developing countries.
Animal genetic resources are part of the biological diversity of the planet. Their genetic variation is being threatened as a result of the increasing intensification of animal production. This article argues in support of the need for sustainable use of animal genetic resources and for a new international approach to the subject. The needs at national, regional and global levels are outlined and recent progress in the creation of infrastructures such as gene and data banks is reviewed. An outline is given of the measures that are still needed to ensure that the increasing use of animal genetic resources in the era of biotechnology is both rational and planned and that animal genetic variation is preserved for unknown future needs.
Unrestricted national development of the planet's resources is depleting biological diversity. The growing human population's demand for basic necessities and its increasing expectations of a higher-quality lifestyle, are pushing natural resources out of balance. For millennia, the world's farmers and livestock producers used thousands of domestic plant and animal genotypes developed by their ancestors. Biotic cycles were stable. Production was sustainable. Today more intrusive human intervention and management of biological habitats may be resulting in increased food output but it is also threatening biological diversity. For this reason, FAO advocates sustainable development, which is defined as follows:
"Sustainable development is the management and conservation of the natural resource base, and the orientation of technological and institutional change, in such a manner as to ensure the attainment and continued satisfaction of human needs for present and future generations. Such sustainable development (in the agriculture, forestry and fisheries sectors) conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable."
Sahiwal bull, Pakistan - Taureau Sahiwal (Pakistan) - Toro Sahiwal, Pakistan
Criollo bull - Taureau Criollo - Toro Criollo
This approach holds resources in trust for the future and includes a viable mechanism for doing so: rational and controlled use. Its objective is to meet present needs without sacrificing the future. This article is concerned with only one aspect of biological diversity; namely animal genetic resources, including all the domestic mammalian livestock and poultry species used by humans for food, fibre and draught animal power. The eras through which human society has used these animal resources are summarized below.
· Domestication: 9000-5000 BC. Centres of origin.· Migration of human populations with their domestic animals: 5000 BC-1700 AD. Adaptation of animals to hostile environments; isolation; genetic drift, natural and human selection. Result: an enormous number of highly adapted animal breeds within each domestic species.
· Controlled matings: 1700-1945 AD. Herd books for registrations; more intensive selection for preferred types.
· Application of science: l 945 onwards. Artificial insemination; freezing of semen; new quantitative methods for selection of desired traits; computers; selection of inbred populations; cross-breeding; large-scale international movement of semen and livestock.
· Era of biotechnology: 1980s onwards. This technology was applied decades earlier at the farm production level. Its potential is so great and production attractions so rewarding that continued progress in related applications is inevitable; e.g. embryo manipulation, including splitting, cloning, sexing; in vitro fertilization; transgenic animals with designer gene mix; new applications of quantitative genetics; hormonal control of the life processes of reproduction, growth and lactation.
Current changes are tending to deplete biological diversity. But why should efforts be made to preserve endangered breeds? Some argue that there is no need to be concerned since automatic economic and market adjustments will take place. Others feel that the loss of unique genetic material is unacceptable. These arguments have been widely debated and are presented in summary here.
The case against formal mechanisms for the preservation of genetic resources essentially states that if a breed is economically useful it will be preserved by market forces. The counter argument, that its utility may well be in another time and place, is refuted by anti-preservationists who maintain that competent breeders and breeding companies will take steps to ensure that all the genetic variation they may need in the future remains available to them. While this argument may have validity in the case of some domestic animal species in developed countries, clearly it does not hold in developing countries where many indigenous breeds are of no interest to anyone other than their current owners, who are crossing them increasingly with exotic breeds.
The other case against preservation is the cost involved. It is a plausible argument: modern society is reluctant to fund a very long-term project for which no economic or financial returns can be quantified and where, for some preserved breeds, there may indeed never be any.
The large genetic variability within the few domestic animal species is disappearing through breed substitution and cross-breeding. Many indigenous breeds, especially in developing countries, have special adaptive traits, such as disease resistance, climatic tolerance and the ability to digest low-quality feed and to survive with reduced or uncertain supplies of feed and water. Although difficult to quantify, it is likely that they also have an excellent ability to convert limited and poor-quality feed into protein. There is a lack of scientific, economic and genetic evaluation of pure-bred indigenous and exotic breeds, in crosses and in different environments. In the future, because of changing circumstances for livestock production and animal products, the genetic variations which exist in these breeds may be indispensable.
The case for preservation is based on the economic imperatives for ensuring flexibility in future animal production, since market forces alone are not adequate to deal with the problem and future needs cannot be anticipated; the scientific value of the genetic material; and the human interest in genetic heritage. All are valid reasons for establishing preservation programmes while utilization is intensified. The underlying economic motive is insurance, an aspect of sustainable development. Since future economic returns cannot be calculated, the question of whether to preserve is highly dependent on the costs of establishing and operating preservation programmes. The cryogenic storage of semen and embryos is a method that entails very low maintenance costs once the samples have been collected. It is a cheap form of ex situ insurance, which imposes minimum restrictions on the current use of preferred biotypes and which can be implemented without awaiting either full documentation of breeds at risk or their extinction.
Awassi ram Pakistan - Bélier Awassi (Pakistan) - Carnero Awassi, Pakistán
Awassi ewe Pakistan - Brebis Awassi (Pakistan) - Oveja Awassi, Pakistán
Alpaca in the Andes - Alpagas (Andes) - Alpacas de los Andes
The concept of sustainable development recognizes that human needs and expectations cannot be halted in the interests of retaining biological diversity in its present state. Biological diversity is, in any case, dynamic. In an unmanaged ecosystem, survival and loss occur naturally. There is no rationale, therefore, for freezing the present populations of animal genetic resources. Change in a managed ecosystem will also occur. Management systems should, however, allow for future change to earlier, different or innovative ecosystems. Change should not preclude such future options by failing to preserve biological diversity that is currently not needed.
Such an approach to sustainable development of animal genetic resources must combine a number of components:
· evaluation of animal genetic resources;· accessible documentation;
· informed use;
· appropriate conservation, in situ and/or ex situ;
· World Watch List;
· Early Warning System;
· appraisal of links with wild ancestors of domestic livestock and poultry, feral populations and wildlife; and
· evaluation of emerging biotechnologies.
An action programme for sustainable development of animal genetic resources
An effective programme must be global in scope, integrating both improved use and conservation. To be effective, national programmes should be planned as part of a regional or global strategy while taking account of local issues. There is also a need for the creation of institutional infrastructures to provide support and direction for national plans. In addition, both national and global components need support through training, publications, finance, surveys and evaluation.
Following is an analysis of measures that are already in place and those that are needed for the full development of a global action programme for sustainable development of animal genetic resources.
Global infrastructures
Global Animal Genetic Data Bank. In 1988, FAO and the European Association for Animal Production (EAAP) joined interests and activities for the enlargement of the EAAP Data Bank. Initially established to serve the interests of European countries, the bank has now been extended to include data from all countries of the world. This Global Animal Genetic Data Bank is located at the University of Hannover in Germany. The first inputs from developing countries will flow via the regional animal gene banks, stocked from national sources, and will include the genetic characterizations and population census data. In addition, in 1989 work started on the transfer of such data from the national animal genetic data banks in China and India. Standard software and format systems are being developed so that information can flow regularly both ways. It is hoped that other developing countries, having their own national animal genetic data banks, will use the same standards and thus facilitate a uniform global system.
The Global Animal Genetic Data Bank and the Animal Descriptors, developed by FAO and the United Nations Environment Programme (UNEP) in 1986, are flexible and open-ended so that data can be updated and new traits included. The bank is also expected to be of value not only for preservation activities but also for planners, project designers, governments, extension workers, teaching institutions and commercial interests in the improved use of animal genetic resources. A hardcopy output, based on a standard numerical format but which prints in different languages, is being studied so that language will not be a barrier either to input or access.
Regional animal gene banks. Following extensive trials and studies, the FAO Animal Genetic Resources Group decided that the most appropriate mechanisms for the preservation of endangered breeds are regional animal gene banks for the cryogenic storage of semen, embryos, deoxyribonucleic acid (DNA) and later, if technically appropriate, of oocytes. During 1988, therefore, regional banks were established in Africa (Ethiopia and Senegal), Asia (China and India) and Latin America (Argentina, Brasil and Mexico). These centres are located in national facilities in each country, supplemented with any necessary equipment and supplies from FAO. There is more than one centre in each region so that split samples can be stored and thus the risk of losses reduced. The centre in Mexico serves the disease-free zone-of Central America and it is hoped that it will soon be possible to start a similar regional bank in the Near East Region. Countries wishing -to store germplasm of their endangered breeds will be responsible for the collection of samples and for shipping them to their regional centre. Blood samples will be taken from each donor animal, both for blood typing and also for DNA extraction and permanent storage. The Animal Descriptors will also be completed for each breed entering the regional bank, so that there will be a genetic record for future use.
Documentation will also include the results of prescribed animal health tests carried out on donor animals. The disease status of the country in which stored germplasm will eventually be used may be different from that of the donor population. Health tests and full documentation of tests done and diseases observed in donor animals are therefore important. Legally, the ownership of the germplasm in the gene banks will remain with the country of origin, with provision made for appropriate access by interested parties presenting valid claims for its use. Users will also be expected to replenish the gene bank when possible with semen or embryos from the regenerated animals.
A new method of preservation now emerging is the preservation of sequences of catalogued DNA in perpetuity. Storage of catalogued DNA is already possible but there are currently at least two problems which are preventing it from becoming the normal method of preservation. One is the fact that genome maps are not yet available to identify which sequences of DNA are responsible for specific traits in- the live animal. The second is that the use of stored DNA to recreate an animal with specific traits is not yet possible as DNA reinsertion techniques with animal cells still produce random results. Nevertheless, in planning such a long-term project as the preservation of endangered breeds, the prospects of DNA storage as a method for the future must be taken seriously. DNA also has the advantage of being a chemical: it is not viewed as biological material by quarantine authorities. Thus, DNA may be moved freely around the world whereas- the movement of animals and germplasm is subject to restrictions because of disease risks.
The collection of semen and embryos is difficult in some developing countries. Semen is often easier to collect although, with males unused to AI in remote locations, this too may be uncertain. Electro-ejaculation is a possibility. The collection of embryos is more expensive and also uncertain because of the unknown hormonal responses of different indigenous breeds to multiple ovulation embryo transfer (MOET) treatment. There is also the fact that, for some species, it is still difficult or impossible to collect and successfully freeze semen and embryos. Ideally, cryogenic stores should be accompanied by the preservation of live animals. However, this cannot be assured under the present conditions of many developing countries. If the last live females of a breed die and there are cryogenic stores of semen and embryos, then live animals may be regained through the use of recipient mothers of another breed of the same species-. This process clearly requires: the storage of representative samples of embryos and, as already indicated, these are difficult and expensive to obtain.
A different approach is therefore being considered and is currently being developed using cattle. The technique involves the cloning of embryos at the 16 or 32 cell stage. By this method, the nucleus from each cell is removed and inserted into an enucleated oocyte taken from the ovary of a cow at the abattoir. The new combined cell develops into a new embryo. Thus, there is the potential for 16 to 32 new clones from one embryo. The possibility of repeating this multiplication with the next generation of eggs has also been reported and, if it proves successful, should open the way to extensive cloning.
When fully developed, the technique will offer an alternative approach to the preservation of genetic variation of endangered breeds in developing countries. Since all the genetic variation of a breed is contained in the semen of a properly constituted, representative and random sample of males, the storage of large numbers of both embryos and semen is no longer essential to preserve the full range of genetic variation. The special value of storing embryos with semen has so far been foreseen as a means to overcome the practical problem of regaining live animals of the breed in pure form. Using currently available techniques, each stored embryo can be expected to provide only one live animal. It has therefore been envisaged that several embryos should be stored together with semen. In this way, it is expected that a population of pure-bred live animals could be regained. However, again given the techniques currently available, in the absence of stored embryos the samples of semen would have to be used in a long process of cross-breeding over several generations, starting with females from other breeds. Only in this way would it eventually be possible to achieve a high level of original breed purity with semen.
The advantage of the new approach now being researched is that the full genetic variation in diploid form could be regained by preserving only a few embryos together with semen from a representative sample of males. In an extreme case, the breed could in fact be regained through embryos from only one female, albeit with a population of half-sib families. This situation would need a careful mating programme for use of the semen in subsequent generations of animals deriving from the half-sib families.
The procedure of the proposed new method, when fully operational, would be as follows: at the time that the live animals are regained, the few embryos would be taken from the cryogenic store and multiplied using oocytes (as already described). This would produce several embryos with an identical diploid variation, which could then be inserted in recipient females of another breed. The mature females resulting from these cloned embryos would then be inseminated with semen from the gene bank, thereby regenerating the full genetic variation in diploid form.
Although the idea of using just a few embryos may not be considered ideal, it should be weighed against the difficulties of the current practice, i.e. the collection of larger numbers of embryos from many females in order to guarantee that the population regained possesses the full diploid genetic -variation of the original breed. The costs and practical difficulties involved in collecting such a quantity of embryos from several individual donor females of an endangered breed are substantial at present, especially in many developing countries. The new technique is currently being developed with cattle, but clearly it will become a very attractive research target in the near future and may later be suitable for other species. It can therefore be expected to make a significant contribution to reducing the difficulties and costs of cryogenic storage of embryos from developing countries in regional animal gene banks.
World Watch-List. The flow of data from participating countries via the regional animal gene banks into the Global Animal Genetic Data Bank will permit a regular appraisal of the status of breeds. This can only be done effectively at a global centre since few breeds exist in one country alone. The analysis of data will focus on the population census and the genetic characterizations.
Sahiwal cow, India - Vache Sahiwal (Inde) - Vaca Sahiwal, India
Murrah buffalo, India - Buffle Murrah (Inde) - Búfalo Murrah India
Photo/Foto: ICAR
Minimum number of females required to maintain a breed - Nombre minimal de femelles nécessaires pour maintenir une race - Número mínimo de hembras necesario para mantener una raza
|
|
No. of breeding females |
|
|
Alderson |
Maijala |
|
|
Cattle |
750 |
1000 |
|
Sheep |
1500 |
500 |
|
Pigs |
150 |
200 |
|
Horses |
1000 |
- |
|
Goats |
500 |
200 |
The World Watch List will be updated periodically with additional information received by the Global Animal Genetic Data Bank. It will provide a much improved alternative to the existing methods of accessing genetic characterizations through publications. Many such publications have been issued by FAO over the last 20 years and have focused on the animal genetic resources of large countries, regions and species that are of special interest. Such publications soon become dated and are expensive to update and reissue. Thus, new information is frequently not accessible. A survey carried out by FAO and UNEP in 12 developing countries showed that only 25 percent of the locally available or nationally published papers, articles, theses and surveys on indigenous animals have ever appeared in the international abstracting services of Animal Breeding Abstracts and AGRIS (International Information System for the Agricultural Sciences and Technology). This is a severe restriction of valuable information and can lead to repetitive work being carried out later, even in a neighbouring country. The periodic publication of the World Watch List, which will include the latest data sent by national institutions to the Global Bank, should ensure better use of information on both genetic characterizations and census data.
In the future, there will be a new and growing need to document and make accessible the genome maps of transgenic domestic animals. The technique of inserting recombinant DNA is growing. Experimenting with mice, laboratory personnel - who are probably in the lead among mammalian researchers producing new types of transgenic animals - have already established their own common system of identifying these lines. Such information is critically important and will become increasingly so for the commercial user of domestic animals as well as for the researcher. It is anticipated that the Global Animal Genetic Data Bank in Hannover will become the chief international centre for this type of information. Such a centre will be invaluable for decision-makers at all levels and could play an important role in ensuring that the future use of animal genetic resources is operated at a sustainable, and not a destructive, level.
Early Warning System. A risk assessment method needs to be established, covering breeds already endangered as well as those varying between the no-risk stage and total loss.
Various estimates have been made as to the minimum number of live animals required to maintain a breed in developed countries. Alderson (1981) and Maijala et al. (1984) provide estimates of breed population sizes for four or five animal species (see Table).
The authors' estimated minimum population sizes, ranging from 150 to 1500 animals, refer to endangered breed populations in developed countries and are at best indicative figures. In developing countries, and particularly in harsh environments, some additional factors must be considered. Geographic distribution of a breed can lead to the clustering of effective breeding sire lines. Thus, subdivisions and genetic isolation of nomadic breeding populations can double or treble the effective population size needed to maintain a breed above the endangered threshold size. Furthermore, the risk of population loss, resulting from disease or adverse climatic conditions such as drought, makes it clear that much higher breed population sizes than those suggested by Alderson and Maijala may be needed in most developing countries.
Consequently, much greater caution must be exercised when the "survival" of endangered breeds in developing countries is in question. FAO uses a working rule that when a population size falls to 5000 breeding females (total population of about 10000 animals), the survival risk of the breed should be studied and appropriate actions initiated. Action taken will depend on the local circumstances of the breed, the management system, the extent of cross-breeding, the rate of decline in numbers and the certainty that the breed has unique qualities. According to established principles, specific recommendations will then be made for each circumstance.
The FAO Early Warning System will inform governments of which breeds are approaching the danger level. By assessing a population's rate of decline over a period of years (using several surveys), the Early Warning System will also predict which endangered breeds could be saved through appropriate anticipatory action. At present, changes in breed populations are often uncharted in many developing countries. As a consequence, breeds are disappearing without having been adequately characterized. Some local breeds are an exception; the Kouri cattle of Chad and neighbouring countries, for example, which have a unique appearance and therefore attract international attention and funding for preservation. Unfortunately, many local breeds of undistinguished appearance are disappearing without it even being known whether or not they have unique genetic adaptive traits.
The situation of the tropical forests, where many species are disappearing without having been identified or named, is comparable in type, though not in scale. In the case of domestic livestock, most breeds have a local name, but there is often no objective documentation on their performance and adaptive abilities. To await such comprehensive documentation before starting preservation activities would be too late. It is for this reason that the Early Warning System is so important as a form of global infrastructure to aid rational decision-making.
Live animal preservation (in situ). Until a few decades ago the preservation of rare breeds was largely a hobby of individuals who kept a few such animals for their own interest. Additionally, some zoological gardens kept a few specimens. These preservation activities were largely limited to breeds of curious appearance. Preservation measures have been taken by governments in Eastern European countries where herds and flocks of domestic landrace breeds have been maintained on some state farms. Apart from these formerly socialist countries, in most other countries little government interest and virtually no public finance has been involved.
More recently, there has been growing public awareness of the serious losses likely to occur in the absence of more planned preservation programmes. An increasing amount of private and semi-private activity has occurred in Western Europe as well as in Canada and the United States. The active support groups vary from country to country. Livestock parks where rare breeds are shown to the public are growing in popularity. Occasionally, government finance is made available to specially designated organizations or to owners for each animal of a recognized endangered breed that they keep and breed regularly. The prolific Taihu sheep in China are an example of this support method. Live animal preservation has several advantages. A breed can gradually respond to changing external influences, and performance evaluations are possible. However, because of high costs, only small populations can be kept and, even in the best-designed breeding programmes, genetic variability tends to decline. There is also the danger of losing a unique herd through disease. Smith (1984) provides estimates of the minimum size of a breeding unit and the number of breeding animals that should be replaced annually for cattle, sheep, pigs and poultry if inbreeding levels are to be kept at about 0.2 percent per year. A tolerable inbreeding level is 1 percent per generation, for which a herd size of about 100 animals is necessary.
In developing countries there are fewer possibilities for live animal reserves. This is because of limited national resources and a lower level of interest on the part of the general public in viewing such animals. In a few countries, FAO has been asked for technical aid in establishing such domestic animal reserves, and a relevant manual is to be published.
Non-governmental organizations
In 1989, the first International Conference of Non-governmental Organizations (NGOs) on Animal Genetic Resources, sponsored by the Rare Breeds Survival Trust, was held in the United Kingdom. Considerable interest and participation was shown and, as a result, a permanent international organization is now in the process of being formed. It will have a unique role and will complement governmental actions in the preservation of domestic animals and poultry, since it will be able to mobilize individual enthusiasts.
The necessary technical infrastructure at global and regional levels is already in place to support the sustainable development of animal genetic resources. However, much work is now required to make the programme operational. This includes the design of national programmes that suit the specific species, breeds, needs and human resources of individual countries care is needed to provide links with the regional and global gene and data banks and links with wildlife and the species related-to domestic and feral populations should also be maintained. Training programmes for nationals are also essential.
There is still an urgent need for an international fund for the sustainable development of animal genetic resources and for an intergovernmental commission to decide policy and direction for a secretariat whose only task should be to implement this programme. Also required is an international legal instrument supporting the sustainable development of animal genetic resources and providing agreed terms for access, use, research and maintenance of genetic resources at risk.
However, in 1989 the FAO Conference (the Organization's supreme governing body) proposed the establishment of institutional infrastructures, including an FAO commission on animal genetic resources with an associated secretariat, an international fund and a legal instrument, which is expected to be a protocol in accordance with the general provisions of the International Convention on Biological Diversity, now being developed by the United Nations.
In the last ten years, the technical tasks that were originally identified by the 1980 FAO/UNEP Technical Consultation as those necessary for the sustainable development of animal genetic resources have been completed. The important technical infrastructure is now in place and is operating modestly.
The time for technical talk is over. The issues are clear. What is now needed is an effective international decision to fund the activities that all agree are necessary at the global, regional and national levels. FAO intends to achieve this goal.
Alderson, L. 1981. FAO Animal Production and Health Paper, 24: 53-76. Rome, FAO.
Maijala, K., Chevekaev, A.V., Devillard, J.-M., Reklewski, Z., Rognoni, G., Simon, D.L. & Steane, D.E. 1984. Conservation of Animal Genetic Resources in Europe (EAAP working party report). Livestock Prod. Sci., 11: 3-22.
Smith, C. 1984. FAO Animal Production and Health Paper, 44(1): 20-30. Rome, FAO.
