Polymorphism of yak blood groups depending on coat color and collection

Abstract

Yaks of the Republic of Tyva are characterised by high biological diversity, expressed by a wide range of body colours and polymorphism of blood groups. According to the distribution of colour and polymorphic blood systems in bulls and yak dams, the most characteristic colours are black, black-and-white, and brown; their frequency in the population is 0.403, 0.148 and 0.118, respectively. Animals of other colour patterns were encountered with a frequency ranging from 0.004 to 0.091. Differentiation of yak bulls and dams by the presence or absence of horns showed that in polled bulls and dams, the frequency of markers Q, L', F of the blood systems B, C, F-V is higher (from 0.250 to 0.846) than in horned ones (0.100–0.500). Blood markers R2, W, X1, U' systems C, and S were identified in polled bulls and dams with a frequency of 0.018–0.143, not found in horned bulls and dams. The frequency of blood antigens G2, T2, I2, E'2, Y', J2 of systems B, J is higher in horned bulls and dams (from 0.200 to 0.800) than in polled individuals (0.054–0.464), and S1 of blood system S was detected only in horned queens. Blood markers I1, Y2, R2, W, X1, and U' systems B, C, and S were undetected in horned bulls and dams. In polled and horned bulls, the frequency of genes E'2, E, X2, V, Z of blood systems B, C, F-V, and Z is higher; they are detected with a frequency of 0.333 to 1.000, regardless of colour. Polled bulls of grey colour do not have markers A2, G2, I1, O2, Y', Y2, Q', Y', X1 blood systems A, B, C, and brown colour - A2, O2, Q', F, U, U' blood systems A, B, F-V, S. Still, in polled bulls with black and brown colours, blood antigens I1, X1 were identified, which are absent in horned individuals of different colours. In yaks, statistically significant differences were noted in colour, polledness and antigens A2, G2, I1, I2, Q, T2, E'2, I', Y', R2, W, X1, X2, L', F, V, J2, H', U, U', Z.