1. Graduate School of Life and Environmental Sciences, University of Tsukuba , Tsukuba 305-8577, Japan
2. Life Science Center for Survival Dynamics, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba , Tsukuba 305-8577, Japan
3. Precursory Research for Embryonic Science and Technology (PREST), Japan Science and Technology Agency (JST) , Tokyo 102-0076, Japan
4. Department of Biological Information, Tokyo Institute of Technology , Meguro, Tokyo 152-8550, Japan
5. College of Biological Sciences, University of Tsukuba , Tsukuba 305-8577, Japan
6. Comparative Genomics Laboratory, National Institute of Genetics , Mishima, Shizuoka 411-8540, Japan