Genetic diversity of Iranian Lori-Bakhtiari sheep assessed by pedigree analysis

- The estimated realized effective population size of the Lori-Bakhtiari sheep was in acceptable level.
- About 75% of total genetic variation was explained by the 38 most influential ancestors.
- Population has lost a part of its genetic diversity compared to the founder population.

In this study a pedigree analysis was conducted to characterize the genetic structure and diversity of the closed nucleus of Iranian Lori-Bakhtiari sheep. Herdbook information collected between 1992 and 2014, was used to estimate generation interval, pedigree completeness level, inbreeding and its evolution during the studied years. Animals born between 2011 and 2014 were selected as a reference population for estimating parameters derived from probability of gene origins. The mean generation interval was 3.42 year in the studied period. Average inbreeding coefficient of the animals in the reference population was 1.02%. The rate of inbreeding was 0.17% per generation (P < 0.01) in the studied period. Realized effective population size estimated from individual increase in coancestry was 101. The effective number of founders, effective number of ancestors and founder genome equivalent of the reference population were 77, 43 and 21 respectively. The results indicated that population under study has fairly good genetic diversity. However, population has lost a part of its genetic diversity due to unbalanced contribution of founders, bottlenecks and genetic drift. For continued genetic gain, enlarging the selection basis and implementation of methods that maximize the selection response at an acceptable level of inbreeding are recommended.