IN SITU

1.3 Live Animal Conservation There are three methods for the conservation of animal genetic resources. The first involves the conservation of animal genetic material in the form of living ova, embryos or semen stored cryogenically in liquid nitrogen (-196 degrees centigrade). The second is the preservation of genetic information as DNA, stored in frozen samples of blood or other animal tissue or as DNA segments. The third is the conservation of live populations.

The advantages, disadvantages and potentials for co-ordination of these systems are reviewed in chapter 4 of this manual, but all are valuable tools with a role to play in the conservation of animal genetic resources.

At the 1989 FAO Expert Consultation it was agreed that frozen embryo and semen technology was cost effective for long term genetic preservation. It was also recognized, however, that there is no single method of preservation which is optimal for all situations. The conservation of live populations in situ has a number of advantages, and may be the only option available in some instances. In situ conservation is also very flexible in its application and allows for the development and utilization of breeds (Weiner, 1989).

This manual has been prepared to draw together the information and experience of in situ live animal conservation theory and practice as it is found throughout the world. It has been written in parallel with a similar manual for the ex situ preservation of cryogenic material (Hodges, 1990a) and is designed to assist with the planning, development and implementation of conservation projects and therefore incorporates many ideas and principles already described in previous FAO publications (see Appendix 1).

Chapter 2 reviews the source of animal genetic resources and the many influences which have acted over time to produce the wealth of livestock varieties available today. It explains the processes of genetic change, selection and extinction with respect to species, breeds and genes.

The need for conservation is discussed in chapter 3 with consideration of economic potential, scientific use and cultural importance alongside the need to conserve unique and endangered populations. The size of populations considered to be rare at the species, breed and gene level and the effects of small population size on genetic variation within populations are all discussed.

Chapter 4 outlines the methods of conservation for live populations beginning with a survey of the advantages and disadvantages of in situ and ex situ conservation. The idea of conserving through separate breeds or composite gene pools are considered along with sampling techniques, selection and methods of random or pedigree mating in small populations.

In the final chapter the practical application of in situ conservation programmes are reviewed with examples from throughout the world.

The summary includes a flow chart for the identification of populations in need of conservation, strategies for conservation and suggestions for the implementation of programmes to conserve animal genetic resources in situ.