Impact of biotechnology on (cross)breeding programmes in pigs

Crossbreeding programmes in pigs exploit between breed complementarity of a dditive genetic effects and heterosis generated by non-additive genetic eff ects. Within breed, improvement programmes may focus on additive effects an d hence the enhancement of complementarity, but non-additive variation is n ot generally used in within line selection or for mate selection at the mul tiplier or commercial level. In this paper, we discuss the impact of new bi otechnological tools, particularly molecular markers, multiple ovulation an d embryo transfer (MOET), and cloning, on structures and methods in crossbr eeding. At the between line level, genetic marker information could allow b etter prediction of heterosis in novel crosses from information on genetic distances. Within the crossbreeding structure, the same technique might be applied at the multiplier and commercial level to exploit specific combinin g abilities of particular animals. Combining simple MOET and cloning protoc ols could radically alter the dissemination of crossbreeding benefits and t heir delivery to the farmer. The combination of MOET, cloning and genomic t ools could result in speed genetics programmes, i.e. fast introgression and recurrent selection methods. Thus, the ultimate impact of biotechnology wi ll be increased rates of progress, efficient use of variation, reduced gene tic lag, and the removal of one or two tiers in the breeding pyramid. The c osts of new technologies are discussed briefly. (C) 2000 Elsevier Science B .V. All rights reserved.