Study on genetic variability at αS1 and αS2 casein loci in autochthonous goat populations of the Lombardy Alps

In cattle, sheep and goats (Hayes et al., 1993) the casein genes form a cluster, on the chromosome 6, of four tightly linked genes, whose sequence is: αS1-β-αS2-k (Threadgill and Womack, 1990; Ferretti et al., 1990; Gallagher et al., 1994; Rijnkles et al., 1997). For this reason the alleles at these loci are generally inherited all together (Di Stasio and Mariani, 2000), with low recombination frequency. Thus it is worth noting the importance of describing the casein haplotypes namely the inherited combination of closely linked alleles (King and Stansfield, 1985; Meuwissen and Goddard, 2001). The knowledge of the casein allele associations could be important for the selection. In goat milk the casein alleles are related to important differences in the level of synthesis of the respective gene products and in milk chemical-physical properties........