CHEMOSENSORY IDENTITY OF H-2 HETEROZYGOTES

  • 1 January 1984
    • journal article
    • research article
    • Vol. 1  (2) , 79-82
Abstract
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. Whether the odor phenotypes of H-2 heterozygotes have distinctive features due to H-2 heterozygosity per se was studied 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 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. The purpose of the transfer-of-training scheme with coded samples is to rule out errors of interpretation that may possibly arise from new learning of hypothetical cues unrelated to genotype or from inadvertent prompting by the operators of the maze. In the study reported here, the following panels of urine donor mice were assembled: B6-H-2b, (abbreviated bb), congenic B6-H-2k (kk), F1 hybrids (bkF1) and H-2-typed (B6 .times. B6-H-2k)F2 segregants (bbF2, kkF2 and bkF2). Mice trained to select bkF1 urine in preference to bb or kk urine were shown by transfer of training with coded samples to distinguish bkF2 urine from equal mixtures of bbF2 and kkF2 urines. The scent of H-2 heterozygotes is distinguishable from the combined scents of constituent H-2 homozygotes.