Evaluation of polymorphism in ten microsatellite loci in Uruguayan sheep flocks

Validation of a microsatellite panel for parentage testing of locally adapted and commercial goats in Brazil

Brazilian goats are generally kept in small herds and extensive rearing systems, mainly in the northeastern region of the country. Despite production improvement in recent years, the lack of pedigree control has affected genetic progress. This study aimed to validate a panel of 16 microsatellites for parentage testing in locally adapted and commercial goats breeds raised in Brazil, as well as to compare its efficiency with the panel recommended by the Brazilian Ministry of Agriculture, Livestock and Supplies (MAPA) in 2004. The number of alleles and expected heterozygosity (He) per marker ranged from four to 18, and from 0.051 to 0.831, respectively. Using all markers, 100% of parentage cases of the validation dataset were resolved with a strict confidence level of 95%. The 16 microsatellites panel showed adequate exclusion power (99.99%) and identity accuracy (99.99%). Suggestions for improvement of the marker panel endorsed by MAPA are provided.

Power of microsatellite markers for analysis of genetic variation and parentage verification in sheep

We report the genetic analysis of 100 individuals of an elite breeding flock of Afshari sheep with a selected set of eighteen microsatellite markers. A full characterization of this set of eighteen loci was carried out generating allele frequency distributions that were used to estimate the genetic information content of these loci, including genetic variability, inbreeding, individual and parent verification parameters. Disregarding MCMA26 monomorphic pattern, microsatellite loci showed moderate level of polymorphism, as such totally 102 alleles were detected with a mean number of 6 alleles per locus. The average expected heterozygosity was 0.72 (SD = 0.07) and the average Polymorphism Information Content (PIC) was 0.67 (SD = 0.08). Total value of inbreeding based on marker data was estimated as -0.02 so it indicates that inbreeding occurred less than would be expected at random. The overall probability of identity considering all twelve independent loci combined was 3.148E-13 meaning lower than 1 in 31 trillions. The results of this study indicate, despite the selective breeding and closed flock system over a number of generations, a relatively high level of heterozygosity still exists in the representative sheep flock. The high degree of multiallelism and the clear and simple codominant Mendelian inheritance of the set of microsatellites used provide a powerful system for the unique identification of Afshari sheep individuals for fingerprinting purposes and parentage testing.