Wei Chen1, Hua Tang2, Hao Lin3. 1. a Department of Physics, School of Sciences, Center for Genomics and Computational Biology , North China University of Science and Technology , Tangshan 063009 , China. 2. b Department of Pathophysiology , Sichuan Medical University , Luzhou 646000 , China. 3. c Key Laboratory for Neuro-Information of Ministry of Education, Center of Bioinformatics, School of Life Science and Technology , University of Electronic Science and Technology of China , Chengdu 610054 , China.