目的　对用表达序列标签 (ExpressionSequenceTag ,EST)策略从日本血吸虫尾蚴cDNA文库中筛选出的新基因进行功能预测。方法　用NCBI站点的BLASTx及BLASTn程序对所获得的新基因序列进行同源性搜索 ;用NCBIBLAST站点的blasttwosequence程序对同源性高的基因进行核苷酸及氨基酸水平的同源性比较 ;利用motifscaninaProteinsequence对cDNA序列所编码的蛋白质进行结构域搜索。结果　发现一个与曼氏血吸虫尾蚴期特异性 8kDa钙结合蛋白 (Sm8)基因高度同源的日本血吸虫新基因 ,cDNA序列与氨基酸水平的同一性均为 82 % ;蛋白结构域搜索结果显示 ,该cDAN序列所编码的蛋白质具有 2个EF手钙结合位点。结论　用EST策略筛选新基因是一个可行的方法 ,所筛到的日本血吸虫新基因编码一种钙结合蛋白 ,全长编码序列与Sm8基因高度同源 ,对该基因的期特异性及免疫保护性的探讨具有重要的意义。 OBJECTIVE: To predict the function of novel genes screened from cDNA library of Schistosoma japonicum by expression sequence tag (EST) strategy. Methods The BLASTx and BLASTn programs of NCBI were used to search for the homology of the new gene sequences. The homology comparison of the high homology genes was carried out by using the blasttwosequence program of NCBI BLAST site. The nucleotide sequence and amino acid sequence were compared using the motifscanina Protein Sequencing Domain search was performed on the protein encoded by the cDNA sequence. The results showed that a new gene of Schistosoma japonicum whose homology was highly homologous to Sm8 gene of Schistosoma mansoni (8kDa calcium-binding protein) was 82% identical to the amino acid sequence. The protein domain search results showed that the cDAN The sequence encodes a protein that has two EF Ca2 + binding sites. Conclusion Screening of new genes by EST strategy is a feasible method. The screened new gene of Schistosoma japonicum encodes a calcium-binding protein, and the full-length coding sequence is highly homologous to the Sm8 gene. The specificity and immunoprotective The discussion is of great significance.