Origin, functions and chemistry of H-2 regulated odorants

Genes located within the major histocompatibility complex (MHC) of mice are responsible for individual differences in body odor (odor types). In this review we suggest that the MHC genes themselves are responsible for odor differences among MHC-congenic mice. Recent studies indicating that volatile carboxylic acids are at least in part responsible for the individual odors and what this finding implies about the pathway from gene to odorant are also reviewed. We suggest that odorants or their precursors are bound directly by MHC products and are released into serum and concentrated in urine. Finally, possible functions of MHC odor types in mice are enumerated and important future research questions are raised.