NCBI数据库在常见嗜尸性蝇类种属鉴别中的应用

目的探讨NCBI数据库比对分析对常见嗜尸性蝇类种属鉴别中的应用价值。方法收集2009年1月至2012年12月重庆市常见嗜尸性蝇类不同发育历期2科5属7种样本52份，采用Chelexl00法提取mtDNA，利用2对引物扩增细胞色素C氧化酶辅酶I基因，分别截取498bp和841bp相同长度的序列，采用MEGA软件计算种内及种间进化分歧情况，并分别在NCBI数据库进行序列BLAST搜索种属同源性比对分析。结果所得序列种内进化分歧均数在0％～0．7％之间，种问进化分歧均数在7．5％～16．1％之间；7个种属的样本序列Ⅰ和序列Ⅱ分别有5个和6个种属完全比对正确，样本总体的正确率分别达到96．15％和98．08％，Maxident值均在97％以上。结论采用序列同源性比对分析，并借助NCBI数据库强大的检索分析功能，可准确进行常见嗜尸性蝇类的种属鉴定，为法医学死亡时间推断提供重要参考依据。

The application of NCBI in common sarcosaphagous flies species identification

Objective To observe the application value of NCBI in common sarcosaphagous flies species identification. Methods 52 samples of blowflies in different developmental duration were collected in Chongqing city from January 2009 to December 2012. All the samples were identified by morphology inspection, including 7 species of 5 genera belonging to 2 families. The mtDNA was extracted by Chelexl00 method for PCR amplification using two kinds of primer. Sequences divergence of 498bp and 841bp between and within species of cytochrome oxidase subunit I （COI） gene were processed by software of MEGA respectively. The species were tested by using BLAST in NCBI database. Results It was showed that the intraspecific and interspecific variation of the two sequences ranged from 0% to 0. 7% and 7.5% to 16. 1% , respectively. Five and six species were right in identification of two sequences and the accuracy rate was 96. 15% and 98.08%t in 52 samples, respectively. The value of Max ident higher than 97%. Conclusion Sequence alignment combined with retrieval analysis function in NCBI can be effectively used to distinguish the common species of sarcosaphagous flies. It was an important supplementary method of morphology in species identification of forensic entomology for estimation of postmortem interval.