Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Identification of a major gene in F and F data when alleles 1 2 assumed fixed in the parental lines | Genet Sei Evol 1992 24 511-526 Elsevier INRA 511 Original article Identification of a major gene in F1 and F2 data when alleles are assumed fixed in the parental lines LLG Janss JHJ Van Der Werf Wageningen Agricultural University Department of Animal Breeding PO Box 338 6700 AH Wageningen The Netherlands Received 9 August 1991 accepted 27 August 1992 Summary - A maximum likelihood method is described to identify a major gene using F2 and optionally Fl data of an experimental cross. A model which assumed fixation at the major locus in parental lines was investigated by simulation. For large data sets 1 000 observations the likelihood ratio test was conservative and yielded a type I error of 3 at a nominal level of 5 . The power of the test reached 95 for additive and completely dominant effects of 4 and 2 residual SDs respectively. For smaller data sets power decreased. In this model assuming fixation polygenic effects may be ignored but on various other points the model is poorly robust. When Fl data were included any increase in variance from Fl to F2 biased parameter estimates and led to putative detection of a major gene. When alleles segregated in parental lines parameter estimates were also biased unless the average allele frequency was exactly . The model uses only the nonnormality of the distribution due to the major gene and corrections for non-normality due to other sources cannot be made. Use of data and models in which alleles segregate in parents eg F3 data will give better robustness and power. cross major gene maximum likelihood hypothesis testing Resume Identification d un gene majeur en Fl et F2 quand les alleles sont supposes fixes dans les lignées parentales. Get article décrit une methode de maximum de vraisemblance pour identifier un gene majeur à partir de données F2 et éventuelỉement Fl d un croisement experimental. Un modèle supposant un locus majeur avec des alleles fixes dans les lignées parentales est étudié à I aide de simulations. .
