Center for Bioinformation Technology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea.|Center for Bioinformation Technology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea.|Center for Bioinformation Technology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea.|Center for Bioinformation Technology, Institute of Molecular Biology and Genetics, Seoul National University, Seoul 151-742, Republic of Korea.