How consanguinity affect DNA traceability? A study in real extensive production systems

BERETTA, E; ROGBERG MUÑOZ, A; SORARRAIN, N.; SILVA MELLO CESAR, A; LIRÓN, JP; PRANDO, A; RAMELLI, P; POSIK, DM; POFCHER, E; RIPOLI, MV; PERAL-GARCÍA, P; VACA, R; MARIANI, P; BALDO, A; GIOVAMBATTISTA, G

Bruselas, Belgica

Conferencia; Final TRACE conference: “How to trace the origin of food?”; 2009

TRACE Project, EU FP6

Since the early ´90 different authors have envisaged the use of DNA identity to certify the traceability of meat. These works were mainly focused in two main aspects: i) to evaluate the information content of a marker set in a particular breed or group of breeds; ii) to determinate the minimum number of markers needed for an acceptable match probability. In the present work, a set of eleven microsatellites were analyzed in Angus cattle. The objective was to establish the effect of consanguinity in the matching efficiency and the minimum number of markers needed, in a DNA based meat traceability program. Samples were taken from real commercial beef production farms from MERCOSUR, were animals are typically raized under pasture-based extensive conditions. Three groups were sampled: Unrelated Group (UG), Related Group (RG) and a Half-Sib Family (HSF), each with different consanguinity rates. As it was expected, the Number of alleles (Na) was more affected than Heterozigocity (He) when consanguinity rate increase. Na decrease from 7.55 in UG to 4.55 in HSF and gene diversity varied from 0.734 to 0.608, respectively. Exclusion power was higher than 0,999998 and match probability lower than 3.01E-08, for the whole set of markers within each group. Both values were affected when consanguinity increase, however, this set was enough to identify meat from all slaughtered animals in Argentina, in a week, month, and a year. Despite all, the effect of consanguinity was reflected in the minimum number of markers required to reach an acceptable confidence. In this sense, the number of markers needed to identify animals was one or two markers higher in HSF than in UG, to reach the same confidence.