基于核基因和线粒体基因的哺乳动物物种鉴定

Mammal species identification based on mitochondrial and nuclear genes

2018年7月,江西野生动植物司法鉴定中心收到森林公安局查获的哺乳动物检材1份。根据被查方的供述,该检材为自行购买的驴肉。为了查明检材物种种类,森林公安委托我中心对检材进行物种鉴定。利用哺乳动物线粒体Cytb通用引物对检材样品的Cytb基因进行了扩增、测序,将Cytb测序结果与NCBI数据库中的在线Blast检索比对后,初步确认检材为马(Equus caballus)。由于线粒体基因为母系遗传,因此不排除该检材为马骡的可能。为了进一步确定检材是否为马或马骡,本研究同时测定了检材样品的肌酸激酶肌肉(creatine kinase muscle,CKM)核基因序列,同时下载了马和家驴(Equus asinus)的CKM基因序列,构建NJ系统发生树,结果显示本次测定的核基因序列与马的CKM基因聚为一支,而不是与家驴序列聚为一支。综合核基因和线粒体系统树的结果,确认送检检材为马。本案例表明综合线粒体Cytb、CKM基因序列结果可实现对马、驴、马骡或驴骡动物样品的物种鉴定。

In July 2018,Jiangxi Wildlife Judicial Identification Center received a mammal sample,which was seized by the Forest Public Security Bureau.According to the confession of the suspect,the sample is ass meat which purchased alone.In order to ascertain the species of the sample,species identification was entrusted by forest police.Mitochondrial Cytb gene sequence was determined using the Cytb universal primers,and the Blast search was conducted using Cytb gene sequence.It was preliminary identified as Equus caballus.However,the mitochondrial gene is maternally inherited,species of the sample might be mule.In order to determine whether the species is horse or mule,the present study simultaneously sequenced the creatine kinase muscle(CKM)nuclear gene sequence,and also downloaded the CKM gene sequences of related species to construct a NJ phylogenetic tree.The NJ phylogenetic tree showed that the nuclear gene sequence was clustered with horse sequences instead of that of ass.Based on results of phylogenetic trees using Cytb and CKM genes,it was identified as E.caballus.This case demonstrates that the integrated mitochondrial Cytb and CKM genes can be useful for species identification of domestic animals(e.g.horse,ass,mule and hinny).