Association Between Serum Alkaline Phosphatase Variants and the R-O-I Blood Group System in the Australian Merino

Abstract

Rendel and Stormont (1964) reported evidence of a polymorphism in sheep for serum alkaline phosphatase. Starch gel electrophoresis of serum always revealed a single zone of enzyme activity (zone A) on the cathode side of the transferrins. In some samples, however, an additional zone of slower mobility (zone B) was observed closer to the slow a-globulins, and the presence of this zone was closely associated with the presence of soluble blood group substance 0 in the plasma and on the red cells. Associations have also been described between electrophoretically distinguishable serum phosphatase types and the J blood group system of cattle (Rendel and Gahne 1963), and the ABO blood group system of man (Beckman 1964). The blood groups concerned with these associations (R-O-i of sheep, J of cattle, and ABO of man) are serologically closely related (Neimann-Sorensen, Rendel, and Stone 1954), and the finding of simiiar associations with related blood groups in three organisms seems to strengthen the possibility of some general functional relationship between alkaline phosphatase and blood groups. However, the nature of the genetic control of serum alkaline phosphatase is not known, and it is possible that the difference in phosphatase phenotype is due to interaction between the enzyme and certain blood group substances. This suggestion is supported by the artificial induction of B zone alkaline phosphatase activity in the serum of previously B-negative sheep by intravenous injection of saliva containing 0 blood group substance (Rendel et al. 1964).