Probability of random sire exclusion using microsatellite markers for parentage verification

Many microsatellite sequences have been described in the bovine genome. Being highly polymorphic these have been suggested as markers for parentage verification and individual identification in cattle. We have evaluated the use of five highly polymorphic microsatellite markers for parentage verification in 14 breeds of cattle in the UK. Three of the microsatellite loci occur within introns in genes: BoLA DRB3, steroid 21-hydroxylase, and the beta subunit of the follicle-stimulating hormone. The other two are anonymous sites ETH131 and HEL6. Results were analysed by a statistical approach that takes in to account deviations from Hardy-Wienberg equilibrium and linkage disequilibrium for multiple loci. The method of determining the probability of random sire exclusion uses observed genotype frequencies instead of allele frequencies. Independently, the markers used have a probability of between 0.72 and 0.62 of identifying a parentage error, while used together the five markers give, on average across breeds, a probability of 0.99 of excluding an incorrect sire.