Bioinformatics Center, College of Biological Sciences, China Agricultural University, 100094 Beijing, China. chenyongzi77@yahoo.com.cn|Bioinformatics Center, College of Biological Sciences, China Agricultural University, 100094 Beijing, China. chenyongzi77@yahoo.com.cn|Bioinformatics Center, College of Biological Sciences, China Agricultural University, 100094 Beijing, China. chenyongzi77@yahoo.com.cn|Bioinformatics Center, College of Biological Sciences, China Agricultural University, 100094 Beijing, China. chenyongzi77@yahoo.com.cn