An antigen detected by cell-mediated and humoral responses of homogametic individuals against heterogametic individuals of the same species, which are otherwise genetically identical. Antigenic responses of this sort have been demonstrated in mammals, birds, and amphibians. In mammals, the antigen is called H-Y because it acts as a Histocompatibility factor determined by the Y chromosome. The location of the gene encoding the H-Y antigen is not known. However, the gene that induces synthesis of the H-Y antigen in humans is located on the Y chromosome. A homologous locus, which suppresses H-Y production, lies on the distal end of the short arm of the X. The H-Y locus is one of the areas that escapes X-chromosome inactivation (q.v.).
Subjects: Genetics and Genomics.