The map positions of both BPH26 and BPH2 seemed to overlap with each other on the long arm of chromosome 12. Nucleotide and amino acid sequences of BPH26 were entirely identical to those of ASD7 and IR1154–243 (Supplementary Fig. S4 online), which are known to harbor the BPH2 gene12,14,15. The expression analysis by reverse transcriptase (RT)-PCR was conducted using BPH26-NIL, Taichung 65, ASD7, and Norin-PL4. Norin-PL4 included a BPH2 originated from IR1125-243 in the background of the japonica cultivar Asominori15. Actin primers were used in the control amplification. The expressions of the BPH26 gene were observed in all the varieties tested (Fig. 4a).