Experiment
180 F2 animals from reciprocal crosses between inbred strains C57BL/6J and DBA/2J and 35 BXD/Ty (B = C57BL/6J, D = DBA/2J) recombinant inbred (RI) strains were used to identify and confirm QTLs affecting hippocampus weight. Hippocampal weight is 19% greater in progenitor strain C57BL/6J than in progenitor strain DBA/2J. A locus on mouse Chromosome 1, Hipp1, mapped to approximately 83.5 cM near D1Mit145 (LRS = 19.5) in the BXD RI strains and was confirmed with an LRS of 34 in the F2 cross. Hipp1 spans 70 cM - 95 cM on mouse Chromosome 1. Hipp1 maps near Cbm1, a QTL associated with cerebellum weight. Rxrg (retinoid X receptor gamma) and Kcnj9 (potassium inwardly-rectifying channel, subfamily J, member 9) are possible candidates gene for Hipp1. A second locus, Hipp2, mapped to mouse Chromosome 5 at approximately 20 cM near D5Mit352 in the BXD RI strains (LRS = 11.5, suggestive linkage) and confirmed with a maximum LRS of 15.9 in the F2 cross. Hipp2 spans 15 cM - 40 cM on mouse Chromosome 5. Possible candidate genes for Hipp2 included Fgfr3 and gaba receptor genes located at 40 cM on mouse Chromosome 5. C57BL/6J-derived alleles at Hipp1 and Hipp2 appear to increase hippocampal weight in F2 animals. Hipp1 and Hipp2 do not appear to interact.
Analysis Tools