Mouse monoclonal antibodies detect an allotypic determinant common to several ruminant species

A monoclonal antibody against goat immunoglobulins recognizes an allotypic determinant (A1) which is common to goat, sheep, cattle and water buffalo. The frequency of the corresponding gene (A') is about the same in all four species, indicating the existence of a polymorphism that remained stable over a period of about 18-20 million years.