1. Laboratory of Cytogenetics, Division of Bioscience, Graduate School of Environmental Earth Sciences Faculty of Science, Hokkaido University
2. Department of Genetics, Institute for Developmental Research, Aichi Human Service Center
3. Aisin Cosmos R & D Co., Ltd.
4. Present address: Advanced Engineering Center, RIKEN
5. Chromosome Research Unit, Faculty of Science, Hokkaido University
6. Present address: Hokkaido Information University