ENU induced a T to A transversion at position 256362 (Genbank genomic region NC_000077). The mutation is located near the acceptor splice site of intron 16 from the ATG exon, eleven nucleotides from the next exon. (J:173670) Additional incidental mutations were detected in sequencing for the causative mutation, Dock2m2Btlr, and may be present in stocks carrying this mutation.