1. Database Center for Life Science, Joint Support-Center for Data Science Research, Research Organization of Information and Systems, Mishima, Shizuoka 411–8540, Japan
2. National Institute of Informatics, Research Organization of Information and Systems, Tokyo 101–8430, Japan
3. DNA Data Bank of Japan, National Institute of Genetics, Research Organization of Information and Systems, Mishima, Shizuoka 411–8540, Japan