kappa-casein, beta-lactoglobulin and growth hormone allele frequencies andgenetic distances in Nelore, Gyr, Guzera, Caracu, Charolais, Canchim and Santa Gertrudis cattle
The genotypes for kappa-casein (kappa-CN), beta-lactoglobulin (beta-LG) and
growth hormone (GH) were determined by polymerase chain reaction (PCR) and
restriction enzyme digestion in seven breeds of cattle (Nelore, Gyr, Guzer
a, Caracu, Charolais, Canchim and Santa Gertrudis). kappa-Casein had two al
leles with the A allele occurring at a higher frequency in Bos indicus bree
ds (0.93, 0.92 and 0.91% for Gyr, Guzera and Nelore, respectively). The bet
a-lactoglobulin locus had two alleles in all of the breeds. European breeds
had a higher frequency of the beta-LG A allele than Zebu breeds. The GH lo
cus had two alleles (L and V) in Bos taurus and was monomorphic (L allele o
nly) in ail of the Bos indicus breeds evaluated. The highest frequency for
the V allele was observed in Charolais cattle. The markers used revealed a
considerable similarity among breeds, with two main groups being discernibl
e. One group consisted of Zebu and Santa Gertrudis breeds and the other con
sisted of European and Canchim breeds.