Genetic diversity in German Pomeranian Coarsewool sheep and the possibility of breeding for maedi-visna resistance

Abstract. Knowledge of genetic diversity among sheep breeds is essential for conserving genetic resources, in particular when selective-breeding programs are taken into consideration, for example, to enhance disease resistance. Maedi-visna virus (MVV) is an incurable, progressive sheep disease caused by a small-ruminant lentivirus (SRLV) infection. In certain sheep breeds, MVV susceptibility has been associated with the allele E of the ovine transmembrane protein gene (TMEM154), whereas the allele K in a homozygous state is protective. The present study estimated the genetic diversity of the native German Pomeranian Coarsewool (RPL, “Rauhwolliges Pommersches Landschaf”) sheep breed and evaluated the possibility of breeding for MVV resistance. A total of 185 RPL sheep were genotyped using the Illumina ovine 50K single-nucleotide polymorphism (SNP) BeadChip to calculate genetic diversity indicators such as effective population size (Ne13= 116) and Wright's F statistical indices (FIS= 0.005). The mean inbreeding coefficient based on runs of homozygosity (FROH) was 6.2 %, with a moderate correlation (0.42) with the pedigree-based coefficient (FPED). Overall, the calculated genetic diversity parameters indicate that the diversity in the RPL breed is not at risk. Thus, breeding for MVV resistance would be possible without a major loss of genetic diversity due to the relatively high frequency of the allele K (54 %). However, selection for the TMEM154 allele K across the entire breed is not advised until further studies confirm its protective effect against MVV in the RPL breed.