Site-selective RNA scission at two sites for precise genotyping of SNPs by mass spectrometryElectronic supplementary information (ESI) available: 1: confirmation of two-site RNA scission; 2: simultaneous analysis of the two SNP sites in APOE. See http://www.rsc.org/suppdata/cc/b3/b300368j/AK and RM have contributed equally to this work. This work was supported by the Biooriented Technology Research Advancement Institution. The support by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sport, Culture, and Technology, Japan is also acknowledged. We are also grateful to Professor Hiroyuki Aburatani of the University of Tokyo for his valuable advice.