study on milk proteins loci in some decreasing italian cattle breeds研究牛奶蛋白位点在一些降低意大利牛品种.pdfVIP

Study on milk proteins loci in some decreasing Italian cattle breeds (1) P. MERLIN Liliana DI STASIO Osservatorio di Genetica Animale Via Pastrengo, 28, 10128 Torino, Italy Summary The genetic polymorphism of the structural loci of five of the six main lactoproteins, a-lactalbumin, (3-lactoglobulin, a,-,l(3- and x-casein, was examined in Grey Alpine, Norica- Pinzgau, Aosta Black Pied, Aosta Red Pied, Piedmont and Chiana cattle breeds. The analysis is concerned with the gene frequencies at the five loci, the frequencies of the allelic combinations controlled by the genetic unit formed by the three casein loci, the linkage disequilibrium in this cluster of loci, the genetic distance between the populations and the heterozygosity. I. - Introduction In recent the of local livestock breeds has been the years disappearance argument of international meetings ond conferences, where the causes of the reduction of the genetic variability and the reasons and methods for its conservation have been amply discussed. Emphasis has been laid upon the importance of investigating the genetic structure of decreasing populations (e.g., the Round Table on « The conservation of animal genetic resourcesat the 1st World Congress on Genetics Applied to Livestock Production, Madrid, 1974). This work is part .of a wide program of investigations on biochemical and immu- nological polymorphisms in Italian cattle. It intends to describe the milk proteins loci and variability in six decreasing breeds : Grey Alpine (GA), Norica-Pinzgau (NP), Aosta Black Pied (ABP), Aosta Red Pied (ARP), Pied