Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: On the genetic determinism of muscular hypertrophy in the Belgian White and Blue cattle breed | Génét. Sél. Evol. 1985 17 3 359-368 On the genetic determinism of muscular hypertrophy in the Belgian White and Blue cattle breed . I. Experimental data R. HANSET and c. MICHAUX Faculte de Médecine vétérinaire 45 rue des Vétérinaires B-1070 Bruxelles Belgique Summary The inheritance of muscle hypertrophy has been studied in an experiment where Fl cows Belgian Blue X Friesian are backcrossed to Belgian Blue sires. The total weight of the most important muscles in calves slaughtered at the constant weight of 84 kg was the criterion for muscle development. The distribution of this variable in the backcross shows a clear bimodality corresponding to the segregation of 2 alleles in equal proportions. The fitting of a monogenic model by the Weighted Least Squares method has led to the estimations of gene effect and dominance deviation. The difference between the 2 homozygotes amounts to more than 6 times the standard deviation within genotype. It is concluded that a major gene is involved in the determination of muscle hypertrophy in the Belgian Blue cattle breed and that regarding the phenotypic expression considered in this study this gene behaves as a partially recessive gene the heterozygote being near the homozygous normal. The symbol mh for muscular hypertrophy is proposed to identify this major gene. Key -words Belgian White and Blue breed muscle hypertrophy inheritance major gene cattle. Resume Le déterminisme génétique de ĩhypertrophie muscu aire dans la race bovine Blanc-Bleu Beige. I. - Données expérimentaĩes L hérédité de 1 hypertrophie musculaire est étudiée dans une experience OÙ des vaches Fl issues de taureaux de race Blanc-Bleu Beige et de vaches Frisonnes sont croisées en retour à des taureaux de race Blanc-Bleu Beige. Le critère de développement musculaire a été le poids total des muscles les plus plus importants obtenu sur des veaux abattus au poids constant de 84 kg. La distribution de cette variable dans le croisement de retour est nettement .