Parentage identification using single nucleotide polymorphism genotypes: application to product tracing.

Identification of relatives using SNP markers has many possible applications. One is as a route to tracing a food product such as a cut of meat back to its source of origin by identifying the parents of the animal from which the product was derived. We develop methods for using SNP markers with maximum likelihood, allowing for the possibility of genotyping errors that would cause false exclusions by simpler methods. We use expectations of likelihood ratios to consider how gene frequencies in the parental populations, numbers of loci, and error rates affect accuracy. This is further quantified as the risk, the probability that an incorrect sire is identified from a panel that contains many other putative sires including its relatives, using a breeding structure relevant to pig breeding. This appears to be a straightforward and potentially effective means of product tracing.