ENU-induced T to G transversion at base pair 111,271,523 (v38) on chromosome 9, or base pair 264 in the GenBank genomic region NC_000075 encoding Mlh1. The mutation corresponds to residue 86 in the mRNA sequence NM_026810 within exon 1 of 19 total exons. The mutation results in a methionine to arginine substitution at position 1 (M1R) in the MLH1 protein. (J:265207)