ENU-induced C to T transition at base pair 101,644,284 (v38) on chromosome 2, or base pair 5,249 in the GenBank genomic region NC_000068. The mutation corresponds to residue 637 in the mRNA sequence NM_009019 within exon 2 of 2 total exons. The mutation results in a proline to leucine substitution at position 171 (P171L) in the RAG1 protein.