Studying Genetic Diversity in Moghani Sheep Using Pedigree Analysis

Studbook information collected from 1988 to 2011 in Jafarabad breeding station of Moghani sheep, north-west of Iran, related to 9,457 lambs were used to study the genetic diversity and to evaluate the effectiveness of an implemented rotational mating scheme using pedigree analysis. Lambs born during 2009-2011 were considered as reference population. Means inbreeding and average coancestry for the reference population were computed as 0.40 and 0.74%, respectively. The mean generation interval was 4.48 years with a longer generation interval on dam-progeny pathways. Average equivalent complete generation, as a measure of pedigree completeness, was 3.37. Effective population sizes were estimated to be 226 and 276 from the individual rate in coancestry and from the individual increase in inbreeding, respectively. Genealogical parameters estimated based on probabilities of gene origin including the effective numbers of founders, the effective numbers of ancestors, the effective numbers of founder genomes (founder genome equivalents) and the effective numbers of non-founder genomes considering the reference population were estimated as 143, 117, 67, and 126, respectively. Approximately, 50% of the total genetic variation was explained by the 43 most influential ancestors, with a maximum individual contribution of 3.27%. The results indicated that although some evidences on bottlenecks and genetic drift during recent years were identified in the studied population, a considerable genetic variability existed in this population due to implementation of an efficient rotational mating scheme for controlling inbreeding.