Chemosensory identity of H-2 heterozygotes.

Mice can recognize the H-2 haplotypes of other mice by scent, and mice show mating preferences for partners of one H-2 type rather than another, usually for partners of an H-2 type different from their own. This olfactory sensing of H-2 odor phenotypes can favor particular H-2 types and promote H-2 diversity, at least under laboratory conditions. This is one reason why we wished to know whether the odor phenotypes of H-2 heterozygotes have distinctive features due to H-2 heterozygosity per se, because such differences could be a further vehicle for reproductive preferences promoting diversity of H-2. A more general reason for interest in the chemosensory individuality of H-2 heterozygotes is that this may shed light on the physical constitution of H-2-related odor phenotypes. The question addressed in this report is whether mice can distinguish the scent of an H-2 heterozygote from the combined scents of the constituent H-2 homozygotes. As in previous studies, the test system employed was the Y maze, in which mice are trained by water deprivation and reward to distinguish the scents of urine samples from alternative panels of donor mice. The critical distinction of the scent of heterozygotes from the combined scents of constituent homozygotes was tested by the transfer-of-training procedure, in which coded urine samples are presented to the trained mice without reward.(ABSTRACT TRUNCATED AT 250 WORDS)