Blood group factor frequencies in Spanish Merino

Abstract

Blood group factor frequencies in Spanish Merino sheep were determined by testing animals of a large population representative of this breed with reagents reacting to seven sheep blood group systems. Factors Cb and 32 (system C), F30 (system 30), Mb (system M), Bf and F3 (system B) were the most common, all with a frequency higher than 0.9. Factor F16 (system A) showed a very low frequency (less than 0.1), and no animals reacted to factor F5 (system C). Only in four cases (factors Bb, F4, Be and Ca), were differences between sexes significant (< 0.05). Estimates of gene frequencies showed that the alleles A −, C b, D − and M b were the most common (frequencies greater than 0.7), whereas the alleles A b and M a were rare (frequencies less than 0.1) and C a and C − were not present. The role of evolutionary forces in the process of genetic differentiation of Merino varieties in the world are pointed out.