Objectives: To identify the common sarcosaprophagous flies in the Yangtze River Delta based on mitochondrial cytochrome c oxidase subunit Ⅰ(COⅠ) gene sequence and verify the reliability of this method.
Methods: Seven common genetically stable sarcosaprophagous flies in three families and six genera were collected from large domestic pig carcasses placed in the field and cultured in the laboratory for many generations. The whole genome DNA was extracted and the COⅠ gene fragment was amplified. The forward and reverse sequencing was followed by splicing. The base composition of the amplified fragment and the rate of interspecific evolutionary divergence were analyzed by software such as Mega 7.0.26. The phylogenetic tree of COⅠ gene sequence of common necrophagous flies in the Yangtze River Delta was established by neighbor joining (NJ) method and unweighted pair-group method with arithmetic means (UPGMA) method.
Results: The average base composition of different flies was A(30.14%), T(38.23%), C(15.98%), G(15.65%). The rate of interspecific evolutionary divergence ranged from 2.2% to 15.3%, the lowest rate was between Chrysomya megacephala and Chrysomya pinguis, the highest rate was between Muscina stabulans and Boettcherisca peregrina.
Conclusions: COⅠ gene can be used to identify the common necrophagous flies in the Yangtze River Delta.
目的: 利用线粒体细胞色素c氧化酶亚基Ⅰ（cytochrome c oxidase subunit Ⅰ，COⅠ）基因序列对长三角地区常见嗜尸性蝇类物种进行分子鉴定并验证其可靠性。方法: 于野外放置的大型家猪尸体上采集并经实验室多代培养、遗传稳定的长三角地区常见嗜尸性蝇类共3科6属7个物种，提取全基因组DNA后扩增COⅠ基因片段，正反向测序后拼接，通过Mega 7.0.26等软件分析扩增片段的碱基组成和种间进化分歧率，并采用邻接（neighbor joining，NJ）法和非加权组平均法（unweighted pair-group method with arithmetic means，UPGMA）构建长三角地区常见嗜尸性蝇类COⅠ基因序列的系统发育树。结果: 不同蝇类物种的平均碱基组成为A（30.14%）、T（38.23%）、C（15.98%）、G（15.65%）。种间进化分歧率在2.2%~15.3%，最低在大头金蝇和肥躯金蝇之间，最高在厩腐蝇和棕尾别麻蝇之间。结论: 利用COⅠ基因能够较好地鉴别长三角地区的常见嗜尸性蝇类物种。.
Keywords: Yangtze river delta; cytochrome c oxidase subunit Ⅰ; forensic entomology; sarcosaprophagous flies; species identification.