TAILIEUCHUNG - Báo cáo khoa hoc:" Response when an to mass selection identified major gene is segregating"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Response when an to mass selection identified major gene is segregating | Genet. Sei. Evol. 30 1998 313-337 Inra Elsevier Paris . Département de Génétlque Animate BIBLIOTHÉQUE 313 F - 78352 JOUY EN JOSAS CEDEX Original article Response to mass selection when an identified major gene is segregating Ricardo Pong-Wong John A. Woolliams Roslin Institute Edinburgh Roslin Midlothian EH25 9PS UK Received 28 October 1997 accepted 2 June 1998 Abstract - A deterministic model to predict response with mass selection when a major locus is segregating is presented. The model uses a selection index framework in which the weight of the different components included in the index are adjusted to describe the different methods of selection using genotype information as selection criteria. The response over multiple generations to several methods of selection using either the whole genotype effect genotypic methods or only the Mendelian sampling deviation of the major locus Mendelian methods was compared with selection using only performance record phenotypic method . Relevant differences in response between using and ignoring information on the major gene were observed only when the favourable allele was at a low frequency. When the major locus had a completely additive effect all the genotypic or Mendelian methods had a higher cumulated genetic gain in the first 3-4 generations of selection but this advantage was lost thereafter. In the long term without exception all methods using genotype information of an additive major gene had lower cumulated gain than phenotypic selection over a wide range of parameters. The reason for the long-term loss was a reduction in the intensity of selection applied to the polygenic background arising from increasing the differences in the selective advantage between genotype groups. The same trend was observed when the favourable allele of the major locus was completely recessive or dominant with the exception of the cases of a large recessive locus over one phenotypic standard deviation where the extra .

• Báo cáo khoa học
• Báo cáo sinh học hay
• cách trình bày báo cáo
• báo cáo sinh học
• công trình nghiên cứu sinh học
• tài liệu về sinh học