Time of Appearance of Antigenic Factors on Cattle Erythrocytes.

Abstract

The antigenic factors of the B blood group system of cattle are associated into complexes called phenogroups. A phenogroup may consist of from one to 15 factors, and behaves as the product of an allelic gene. The purpose of this work was to inquire if the various factors within a given phenogroup are detectable at the same age of embryologic development, and if the same factors occurring in different phenogroups are detectable at the same age. Ninety embryos of various ages and their dams were blood typed and their phenogroups determined. It was found that the different antigenic factors which comprise a phenogroup do not develop simultaneously in ontogeny and that the same factor develops at different ages depending upon the phenogroup in which it occurs. Thus, insofar as age of development is concerned, the B locus of cattle does not behave as a physiologic unit.