Affiliation: | (1) Present address: Division of Genetics and Mutagenesis, National Istitute of Health Sciences, 1-18-1 Kamiyoga Setagaya-ku, 158 Tokyo, Japan;(2) Present address: Riken Cell Bank, The Institute of Physical and Chemical Research, 3-1-1 Koyadai, 305 Tsukuba Science City, Japan |