G to A transition located in exon 1 and is of predicted to cause a nonsynonymous amino acid change of arginine to histidine at position 109 (R109H). The known genealogy of the DBA-related strains and genotyping analysis of archived DBA/2J DNA samples indicate that this allele occurred in the DBA/2J lineage between 1951 (when it was separated from the DBA/2N lineage) and 1975. (J:139223, J:162868)