MAPPING OF THE MOD-1 LOCUS ON MOUSE CHROMOSOME-9

A new method for typing the Mod-1 locus on mouse Chromosome (Chr) 9 wa s developed, based on restriction fragment length polymorphism (RFLP) within a polymerase chain reaction (PCR)-amplified fragment. The new m ethod led us to revise the strain distribution pattern (SDP) of Mod-1 in the BXD (C57BL/6J x DBA/2J) and AKXD (AKR/J x DBA/2J) recombinant i nbred (RI) strains. The new SDP eliminates several previously reported examples of double recombination events between Mod-1 and the closest flanking loci in the BXD and AKXD strains. In the BXD strains, the re vised SDP of Mod-1 was identical to that of the Mod-1-related D9Rtil l ocus. Thus, the identity of D9Rtil as a Mod-1-related locus rather tha n Mod-1 itself is in question. The method was also applied to an inter specific backcross panel between an inbred strain of Mus musculus molo ssinus (MSM/Ms) and C57BL/6J to map Mod-1 with respect to surrounding microsatellite loci, defining the proximal localization of Mod-1 with respect to D9Mit10 with a genetic distance of 0.6 +/- 0.6 cM.