1 Department of Chromosome Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2‑2‑1 Honjo, Chuo‑Ku, Kumamoto, 860‑0811, Japan. kojik@kumamoto-u.ac.jp.
2 Division of Embryology, National Institute for Basic Biology, 5‑1 Higashiyama, Myodaiji, Okazaki, Aichi, 444‑8787, Japan.