Traceability of 9 Portuguese cattle breeds with PDO products in the market using microsatellites

Assignment tests based on multilocus genotypes are becoming increasingly important to certify the origin of livestock products and assure food safety and authenticity. The potential of microsatellites for determining the origin of beef products among cattle breeds present in the Portuguese market with the Protected Denomination of Origin (PDO) was studied. Methodologies were used to establish the number of populations under study and to allocate individuals to their original population. The STRUCTURE program was used to perform the strictly Bayesian method and the GENECLASS 2 program was used to accomplish two types of assignment tests. The STRUCTURE program converged to 9 populations, precisely the number of populations under study. Regarding the individual allocation, the strictly Bayesian method implemented by the STRUCTURE program allowed 96% of correct allocations when running the program without the knowledge of the source populations and 98% when the STRUCTURE program was run knowing the source populations of the animals. In the assignment test performed by the GENECLASS 2, 95% and 97% of individuals were correctly allocated by the frequency and the Bayesian methods, respectively. These results show the potential feasibility for traceability scheme based on microsatellites.