作者单位:Department of Bioinformatics, School of Life Science and Technology, Tongji University, Siping Rd. No. 1239, Shanghai 200092[1]Department of Computer Science, Hefei University of Technology, Tunxi Rd. No. 193, Hefei 230009, China[2]Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602-7229, USA[3]