EXAMINATION OF GENETIC-LINKAGE BETWEEN PU TATIVE QTL FOR MILK-PRODUCTION TRAITS AND MILK PROTEIN MARKERS USING MARKER ASSISTED COMPLEX SEGREGATION ANALYSIS

Marker assisted complex segregation analysis was applied to estimating the effects and position of a putative quantitative trait locus as we ll as polygenic parameters of five milk production traits and protein to fat ratio based on milk production performances of 1076 cows of Bla ck Pied Dairy Cattle and Holstein Friesian as well as 645 cows of Germ an Black and White. Genetic parameters including the recombination rat e between marker locus and QTL were estimated by maximum likelihood me thod with the aid of the genetic marker information of polymorphic mil k proteins: alpha(S1)-casein, beta-casein, kappa-casein and beta-lacto globulin. No significant QTL effect was detected for the trait protein to fat ratio. Linkage between beta-casein and the QTL of milk and pro tein yield was found, however, the linkage was not significant due to the conservative test criterion. Majorgenic inheritance is not assumed according to the results.