Histocompatibility genes of mice. III. H-1 and H-4, two histocompatibility loci in the first linkage group

Abstract

A new histocompatibility locus, H-₄, in the first linkage group of the mouse, has been identified. The gene-order in this linkage group is H-1, c, p, with H-₄ very close to p but its position relative to p undetermined. There is 8.5±2.1 per cent crossing over between H-₁ and c in the heterozygous female, 5.4±3.7 per cent in the heterozygous male. At least 4 alleles at the H-₁ locus have been identified. The distribution of H-₁ alleles in various inbred and co-isogenic resistant stocks is shown in Table 11. The mean survival of skin grafts made between various co-isogenic strain pairs, differing at H-₁, ranges from 32 to 91 days, with a minimum survival of individual grafts of 20 days and a maximum of 124 days. Ovarian grafts between the same strain pairs show much longer survival. The significance of these results for estimates of gene numbers is discussed; the higher published estimates are favoured.