Genetic diversity in Shirvan Kordi sheep using microsatellite markers and compared to estimation of inbreeding coefficient using pedigree

This study was conducted to estimate coefficient of inbreeding of Shirvan Kordi sheep based on molecular and pedigree information. Pedigree of 7170 lambs produced from 177 rams and 2182 ewes collected during 1989 to 2009 in Shirvan Kordi sheep breeding flock were used for calculating inbreeding coefficient. Average inbreeding coefficient of the flock on base year 1989 was estimated as 0.668%. Coefficient of inbreeding was also estimated in this population using 6 microsatellite markers (BM8125, BMS2361, BM6526, BM6438, BMS1004 and BM6444) and 100 blood samples. A total of 34 alleles with an average of 5.67 was observed for each locus. Within population inbreeding (FIS) in Shirvan Kordi sheep breeding flock ranged from -0.1859 for BM6526 to 0.3329 for BM6438. The FIS estimates were positive for BM6438 and BM6444 loci (0.3329 and 0.2287, respectively) and for the other loci were negative. Average inbreeding coefficient based on marker data was estimated as 0.2617%. Microsatellile loci used in this population showed a high polymorphism and can be used for future genetic studies in this population. These estimates may be closer to the true values using more number of genetic markers across the whole genome and higher sample size. Moreover, the results indicated that the estimates of genetic resemblance between individuals based on allelic contribution of a limited number of loci may not be very accurate for measuring the relationships and making breeding decisions in the flocks. Therefore, estimation of inbreeding coefficients using pedigree is suggested.