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With assignment methods are generally indicated several statistical approaches that use genetic information to identify or verify membership of individuals or groups of individuals. In the present research, the stepwise discriminant analysis (SDA), the canonical discriminant analysis (CDA) and the discriminant analysis (DA) were used to develop an assignment method based on genotypes obtained from the Illumina's OvineSNP50 BeadChip. The three statistical techniques were used to select the most informative markers for discriminating 21 different sheep populations (20 Italian and 1 Slovenian) and their 5 geographic areas of origin. The procedure selected two reduced pools of markers, 110 and 108, that were able to exactly discriminate the 5 geographic areas and the 21 sheep populations, respectively. Moreover, all animals were correctly allocated in the validation procedure. The obtained results indicated that the combined use of the SDA, CDA, and CD techniques represents an efficient strategy for selecting a reduced pool of highly discriminant markers. These SNPs could be further used to develop a low cost customized essay to trace the breed or the geographic area of animals or derived foodstuffs. [ABSTRACT FROM AUTHOR]

The effectiveness of single nucleotide polymorphisms (SNPs) for the assignment of cattle to their source breeds was investigated by analysing a panel of 90 SNPs assayed on 24 European breeds. Breed assignment was performed by comparing the Bayesian and frequentist methods implemented in thestructure 2.2 andgeneclass 2 software programs. The use of SNPs for the reallocation of known individuals to their breeds of origin and the assignment of unknown individuals was tested. In the reallocation tests, the methods implemented instructure 2.2 performed better than those ingeneclass 2, with 96% vs. 85% correct assignments respectively. In contrast, the methods implemented ingeneclass 2 showed a greater correct assignment rate in allocating animals treated as unknowns to a reference dataset (62% vs. 51% and 80% vs. 65% in field tests 1 and 2 respectively). These results demonstrate that SNPs are suitable for the assignment of individuals to reference breeds. The results also indicate thatstructure 2.2 andgeneclass 2 can be complementary tools to assess breed integrity and assignment. Our findings also stress the importance of a high-quality reference dataset in allocation studies. [ABSTRACT FROM AUTHOR]

The verification of the breed origin of animal products is relevant for food safety and authenticity. We assessed the suitability of AFLP molecular markers in the assignment of cattle individuals to their breed of origin. Three hundred and ninety-six animals belonging to 16 cattle breeds genotyped with 141 AFLP markers were used as reference data set. Assignment was performed with likelihood (aflpop) and Bayesian (structure) methods. The Bayesian approach was superior to the likelihood algorithm with respect to (i) the correct assignment of simulated individuals to their breed of origin (93% vs. 81% respectively), (ii) the correct assignment of 44 sampled Romagnola animals (91% vs. 45% respectively) and (iii) the correct classification of animals belonging to a breed that was not included within the reference dataset. Thus, AFLP profiling in combination with the Bayesian approach seems a useful tool for breed assignment. [ABSTRACT FROM AUTHOR]