广西南丹县旋毛虫COX1基因和5S rRNA基因分析

目的分析广西壮族自治区南丹县旋毛虫（Trichinella spiralis）COX1和5SrRNA基因特点,阐述该分离株的系统发生关系及基因变异规律。方法PCR扩增南丹旋毛虫分离株COX1和5SrRNA基因片段并对扩增产物进行测序;应用Blast和ClustalX软件计算其碱基组成,分析该分离株与GenBank中相应序列的同源性及遗传距离,同时应用UPGMA方法分析聚类关系。结果扩增后COX1基因片段长419bp,5SrRNA基因片段长695bp。南丹旋毛虫分离株与Trichinella spiralis（T.spiralis）的同源性最高,分别为99.0%和99.1%,遗传距离最小,分别为0.005和0.014。采用UPGMA法构建的2个系统发生树,南丹分离株和T.spiralis具有高度同源性,位于同一分枝,与无囊包旋毛虫（T.papuae和T.zimbabwensis）分枝较远,后者独成一枝,与T.spiralis相比,2个基因均存在变异,且变异位点均为4个,分别占相应基因序列的1.19%和0.57%。2个基因均富含A和T碱基,A＋T含量分别占相应基因的61.8%和66.4%。COX1变异存在转换和颠换,但均发生在密码子第三位点。5SrRNA基因变异位点分散,但变异均为转换,无颠换。结论南丹旋毛虫分离株与T.spiralis具有高度的亲缘关系,其COX1和5SrRNA基因的碱基组成、变异位点及变异类型均具有偏好现象。

Genetic Analysis of COX1 and 5S rRNA of Trichinella spiralis from Nandan County, Guangxi

Objective To study the characteristics of COX1 and 5S rRNA gene of Trichinella spiralis obtained from Nandan County,Guangxi.Method Genomic DNA was extracted from Nandan isolates.COX1 and 5S rRNA gene fragments were amplified by PCR method and followed by DNA sequencing.The Basic Local Alignment Search Tool(Blast)and Clustal X were used for sequence identification.Genetic distances were computed and phylogenetic trees were constructed with UPGMA method.Result COX1(419 bp)and 5S rRNA(695 bp)gene fragments were amplified.The sequence of COX1 and 5S rRNA gene between Nandan isolates and Trichella spiralis shares 99.0% and 99.1% of sequence homology,respectively.The genetic distance of COX1 and 5S rRNA gene between Nandan isolates and Trichinella spiralis was 0.005 and 0.014,respectively.Phylogenetic analysis revealed that Nandan isolates are homologous to T.spiralis,and are grouped into the sane clade.Non-capsulated trichinella(T.papuae and T.zimbabwensis)were group in another clade.Mutations in COX1(1.19%)and 5S rRNA gene(0.57%)were noted.Both COX1 and 5S rRNA genes are enriched in A and T bases.The contents of A T in COX1 and 5S rRNA is 61.8% and 66.4%,respectively.Transitional and transversional mutations were seen in COX1 gene and all the varations were in the third codon.Only transitional mutation was observed in 5S rRNA gene.Conclusion Nandan isolates are highly homologous to T.spiralis.