tailieunhanh - Báo cáo sinh học: "Genetic evaluation for a quantitative trait controlled by polygenes and a major locus with genotypes not or only partly known"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Genetic evaluation for a quantitative trait controlled by polygenes and a major locus with genotypes not or only partly known | Genet Sei Evol 1993 25 537-555 Elsevier INRA 537 Original article Genetic evaluation for a quantitative trait controlled by polygenes and a major locus with genotypes not or only partly known A Hofer1 Bw Kennedy2 1 Department of Animal Sciences Federal Institute of Technology ETH CH-8092 Zurich Switzerland 2 Centre for Genetic Improvment of Livestock University of Guelph Guelph Ontario NIG 2W1 Canada Received 4 March 1992 accepted 5 August 1993 Summary For a quantitative trait controlled by polygenes and a major locus with 2 alleles equations for the maximum likelihood estimation of major locus genotype effects and polygenic breeding values as well as major allele frequency and major locus genotype probabilities were derived. Because the resulting expressions are computationally un-tractable for practical application possible approximations were compared with 2 other procedures suggested in the literature using stochastic computer simulation. Although the frequency of the favourable allele was seriously underestimated when major locus genotypes were entirely unknown the proposed method compares favourably with the 2 other procedures under certain conditions. None of the procedures compared can satisfactorily separate major genotypic effects from polygenic effects. However the proposed method has some potential for improvement. major locus genetic evaluation segregation analysis Resume - Evaluation génétique pour un caractère quantitatif contrôlé par des polygenes et un locus majeur à genotypes inconnus OU seulement partiellement connus. Pour un caractère contrôlé par des polygenes et un locus majeur à 2 allèles les equations pour I estimation du maximum de vraisemblance des effects génotypiques au locus majeur et des valeurs génétiques polygéniques ont été dérivées permettant aussi d estimer la frequence de 1 allèle majeur et les probabilités des genotypes à ce locus. Les expressions obtenues étant incalculables en pratique des approximations possibles ont été .