Prioritisation of livestock breeds for conservation is agreed to depend upon the genetic distinctiveness of breeds, on census data and degree of endangerment, and on other factors relating to the present, future, or past function of the breeds in the livestock industry. How these factors can be combined to yield a prioritised list needs to be considered. An objective framework for prioritisation can be deduced if breeds are compared with each other by plotting genetic distinctiveness against distinctiveness of function. In this paper, the native British and Irish cattle breeds (n = 31 commercial, minority and rare breeds) have been prioritised in this way. Those with highest conservation priority are Chillingham, Gloucester, Guernsey, Jersey, Shetland and Irish Moiled. The 25 native British sheep breeds that are not on the Rare Breeds Survival Trust (RBST) Watchlist were also considered. The structure of the British sheep industry means that functional distinctiveness of breeds is not easily deduced. The only fully comparable characterisation data relate to wool fibre fineness class, so genetic distinctiveness was plotted against distinctiveness of this attribute. The non-rare breeds with highest conservation priority by this measure were Herdwick, Hampshire Down and Clun Forest.

Characterisation of genetic diversity in a large number of European pig populations has been undertaken with EC support. The populations sampled included local (rare) breeds, national varieties of the major international breeds, commercial lines and the Chinese Meishan breed. A second phase of the project will sample a further 50 Chinese breeds. Neutral genetic markers (AFLP and microsatellites), with individual or bulk typing, were used and compared.

DNA from 59 European pig populations was extracted on samples of about 50 individuals per population. Individuals were typed for 50 microsatellites and for 148 AFLP bands. A subset of 25 populations was typed for 20 microsatellites on pools of DNA. Allele frequencies were estimated by direct allele counting for the co-dominant markers. Frequencies of AFLP negative alleles (absent bands) were obtained by taking the square root of absent band frequencies. Within-breed variability was summarised using standard statistics: expected and observed heterozygosity, mean observed and effective numbers of alleles, and F statistics. Between-breed diversity analysis was based on a bootstrapped Neighbor-Joining (NJ) tree derived from Reynolds distances (DR). The standard distance of Nei (DS) was also calculated.

One of the main objectives in conservation programmes is to maintain the highest levels of genetic variability, for the population to be able to face future environmental changes and to assure long-term response to selection, either natural or artificial (Oldenbroek, 1999, Barker, 2001). The classical measure of genetic diversity is the expected heterozygosity, or gene diversity (GD), but allelic diversity (AD), or the number of different alleles per locus, also has evolutionary importance. Most optimal strategies for conservation have aimed to maximise GD (e.g. Caballero and Toro 2000), but AD has received much less attention. The objective of the present study is to test the efficiency of the maintenance of allelic diversity of strategies based either on the allelic diversity itself or on the expected heterozygosity in a small population, using information from molecular markers.

Sheep are seasonally-polyoestrous short-day breeders. Although the domesticated breeds have longer breeding seasons than the feral breeds, their maximum ovulation rates are only achieved over a relatively short period. The effect of these seasonal shifts in ovarian response on the success of ovum recovery for genetic improvement or breed conservation is unknown. The aim of the present study was to assess the efficiency of ovum recovery procedures for genetic conservation outwith the normal breeding season.