Summary: Bos et al. (2009)

Mate selection is important in many organisms and occurs through multiple trait assessment in a context or condition-dependent manner. Theoretically, mate choice may be based on an individual's genotype, but this requires organisms to self-reference their own genotype. MHC genes may be used in self-referencing as they can be assessed through ligand binding in the vomeronasal organ. Due to overdominance, major histocmpatibility complex (MHC) alleles are likely to be adaptive and there is likely to be negative assoratative mating between individuals. Bos et al. (2009) assessed MHC-based mating preferences in wild, outbred eastern tiger salamanders (Ambystoma tigrinum tigrinum) by genotyping adults and larvae at microsatellite and MHC loci. They aimed to address 4 questions about MHC-based mate choice: 1) Do morphological characteristics increase reproductive success? 2) Is reproductive success in males mediated by the MHC? 3) If yes, are the mating patterns context-dependent? 4) If yes (2 and 3), is variation in male reproductive success linked to MHC-based cues only when large differences are apparent? Bos et al. (2009) found that male reproductive success was positively correlated with increased tail length.They found that MHC-similar males (to females) sired more offspring, indicating that negative assortative mating is not occurring in the population and that MHC-diverent males may be at a reproductive disadvantage. Bos et al. (2009) suggest that MHC-based choice is likely to be influenced by many factors.