Association of fertility, fitness and longevity with the murine Ah locus among (C57BL/6N) (C3H/HeN) recombinant inbred lines

The Ah locus encodes a cytosolic receptor which controls the induction of enzymes that metabolize drugs, chemical carcinogens, and other environmental pollutants. B6NXC3N recombinant inbred lines have been developed from the progenitors C57BL/6N and C3H/HeN inbred mouse strains. Ah phenotyping at each generation has resulted in the establishment of some lines containing high levels of the high-affinity Ah receptor; other lines, very low levels. A genetic model involving two unlinked loci is offered to explain the distribution of Ah receptor levels among (C57BL/6N) (C3H/HeN)F2 individuals. Between generations 7 and 13, individual females and males from the B6NXC3N recombinant inbred lines were crossed with DBA/2N males and females. Presence of high levels of the high-affinity Ah receptor in both female and male B6NXC3N mice was found to be associated with greater fertility, fitness, and longer life span. The data suggest that these parameters are correlated with the Ah locus or a closely segregating gene.