1. Experimental Farm, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
2. Department of Genetics, School of Life Science, Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan
3. Plant Gene Expression Center, U.S. Department of Agriculture-Agricultural Research Service, Plant and Microbial Biology Department, University of California at Berkeley, Albany, California 94710
4. Mammalian Genetics Laboratory, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
5. Pioneer Hi-Bred International, Johnston, Iowa 50131