Laboratory of DNA analysis, Human Genome Centre, Institute of Medical Science, University of Tokyo, Japan. sunk@ims.u-tokyo.ac.jp|Laboratory of DNA analysis, Human Genome Centre, Institute of Medical Science, University of Tokyo, Japan. sunk@ims.u-tokyo.ac.jp|Laboratory of DNA analysis, Human Genome Centre, Institute of Medical Science, University of Tokyo, Japan. sunk@ims.u-tokyo.ac.jp