tailieunhanh - Báo cáo khoa hoc:"Breeding values for identified quantitative trait loci under selection"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học thế giới đề tài: Breeding values for identified quantitative trait loci under selection | 1 2ŨÚ0 Genet. Sei. Evol. 31 1999 421-436 421 Inra Elsevier Paris . . Original article Département de Génétique Animate BIBLIOTHỂQUE T3nn . Breeding values for identified quantitative trait loci under selection Jack . Dekkers Department of Animal Science 225C Kildee Hall Iowa State University Ames IA 50011 USA Received 26 March 1999 accepted 6 July 1999 Abstract - The use of an identified quantitative trait locus QTL in selection requires the integration of breeding values BV for the known QTL with estimates of polygenic BV. For a QTL with two alleles BV for the QTL are traditionally based on the allele substitution effect a a d q p where a and d are additive and dominance effects and p and q are gene frequencies in the current generation. It is shown here that to maximize single generation response BV for a QTL with dominance must be derived based on gene frequencies among selected mates rather than frequencies in the current unselected generation. Because selection affects gene frequencies that in turn affect optimal BV for the QTL gene substitution effects must be derived numerically. Response from selection on optimized versus standard BV for the QTL was evaluated for a range of parameters. Benefits of optimal selection were greatest for intermediate gene frequency and increased with a magnitude of additive and dominance effects up to 9 . Extra response was negligible for gene frequencies less than or greater than . In conclusion strategies for marker-assisted selection that aim to maximize short-term response must account for the effects of dominance and changes in gene frequency at the QTL on performance of future progeny. Inra Elsevier Paris marker-assisted selection dominance breeding values quantitative trait loci Resume Valeurs génétiques pour des loci quantitatifs identifies en situation de selection. L utilisation d un locus quantitatif QTL identifie en selection nécessite 1 intégration .