Optimal use of genetic markers in conservation programmes

Monte Carlo simulations were carried out in order to study the benefits of using molecular markers to minimize the homozygosity by descent in a conser vation scheme of the Iberian pig. A selection criterion is introduced: the overall expected heterozygosity of the group of selected individuals. The m ethod to implement this criterion depends on the type of information availa ble. In the absence of molecular information breeding animals are chosen th at minimize the average group coancestry calculated from pedigree. If compl ete molecular information is known the average group coancestry is calculat ed either from markers alone or by combining pedigree and genotypes with th e markers. When a limited number of markers and alleles per marker are cons idered, the optimal criterion is the average group coancestry based on mark ers. Other alternatives, such as optimal within-family selection and freque ncy-dependent selection, are also analysed. (C) Inra/Elsevier, Paris.