H ‐ Y ANTIGEN: GENETIC CONTROL OF THE EXPRESSION AS DETECTED BY HOST ‐ VERSUS ‐ GRAFT POPLITEAL LYMPH NODE ENLARGEMENT ASSAY MAPS BETWEEN THE T AND H ‐ 2 COMPLEXES

Abstract

We are using the terms 'low' and 'high' expression when the H-Y antigen on thymocytes of mouse parental strains is, respectively, weakly and strongly immunogenic for F1 hybrids in a host-versus-graft popliteal lymph node enlargement assay. Using this assay we attempted to locate the genetic factor(s) responsible for the control of H-Y expression within chromosome 17 since our previous study indicated linkage with the H-2 complex. We produced to this aim recombinants from (B10.T X C3H/Di)F1 hybrids where crossing over took place between H-2 and T complexes. In this way we were able to locate a gene denoted Hye (for H-Y expression) whose 'high' and 'low' alleles originated, respectively, from the B10 and C3H/Di strains. In the recombinants, the expression did not follow the H-2 haplotype, but obviously depended on the position of crossing over between H-2 and T. This pointed to the Hye gene mapping proximally from the H-2 complex.