Frequency distribution of histocompatibility-2 antigenic specificities in the Japanese wild mouse genetically remote from the European subspecies.

Fifty-eight Japanese wild mice, Mus musculus molossinus, collected from twenty-eight localities were surveyed for twelve H-2 antigens using the haemagglutination method. Significantly higher frequencies of H-2.3 and H-2.5 specifities and relatively lower frequencies of the other public specificities were observed. This was confirmed by examining four specificities, H-2.3, 5, 13 and 23, in 370 mice. Quantitative absorption of the alloantisera by erythrocytes and spleen lymphocytes of molossinus mouse revealed definite absorption of H-2.3, 5 and 8 antigens, though their antigenic strength was apparently weaker than the controls, B10 congenic mice. Comparative assay of the strength of H-2.5 antigen in either homozygous and heterozygous conditions distinctly eliminated the possibility of gene-dose effect for the reduced strength of the public antigens in molossinus mouse. To explain this, divergence time between molossinus and domesticus was computed based on the allelic frequency data already reported on ten loci in both subspecies. It is roughly 1.5 x 10(6) years, which could allow for the occurrence of considerable genetic changes in many public antigens, except those conserved through selection.