新疆和田地区于田县牛源环形泰勒虫种群基因型及遗传多样性分析

Analysis of genotypes and genetic diversity of bovine-derived Theileria annulata populations in Yutian County,Hotan Prefecture,Xinjiang Uygur Autonomous Region

为探究新疆和田地区于田县牛源环形泰勒虫种群的基因型分布及遗传多样性,试验首先从该县10个乡镇(阿羌乡、喀尔克尔乡、科克亚乡、木尕拉镇、斯也克乡、先拜巴扎镇、英巴格乡、加依乡、奥依托格拉克乡、阿日希乡)采集疑似环形泰勒虫病患牛血液样本共443份,提取基因组DNA后对牛源环形泰勒虫Tams1基因进行PCR检测,统计10个乡镇牛源环形泰勒虫的阳性样本数及阳性率;然后在发现阳性样本的乡镇中,每个乡镇随机选取2个阳性样本进行测序,将测序结果进行同源性分析并与参考序列共同构建NJ系统发育树,分析基因型;最后对于田县环形泰勒虫种群进行遗传多样性分析。结果表明:在443份牛血液样本中,有93份样本环形泰勒虫检测结果为阳性,阳性率为20.99%;10个乡镇中有9个乡镇牛源环形泰勒虫检测结果为阳性,阳性率在10.45%~45.45%之间,其中阿羌乡阳性率最高,加依乡未检出。18株环形泰勒虫Tams1基因序列的核苷酸相似性为76.0%~100%,同乡镇的2个阳性样本之间的核苷酸相似性为91.0%~100%;这18株牛源环形泰勒虫在NJ系统发育树中未全部聚为一支,一些虫株甚至与其他国内外参考毒株表现出了更近的亲缘关系,但均为G1基因型。于田县G1基因型环形泰勒虫种群多态性位点数为119个,核苷酸多样性为0.053,平均核苷酸差异数为28.95个,单倍型数为12个,单倍型多样性为0.895,Tajima’s D值和Fu and Li’s F值均小于0。说明于田县G1基因型环形泰勒虫种群具有较高的遗传多样性且正在发生扩张。

In order to investigate the genotypic distribution and genetic diversity of bovine-derived Theileria annulata populations in Yutian County,Hotan Prefecture,Xinjiang Uygur Autonomous Region,in the experiment,firstly,a total of 443 blood samples of cattle suspected to be infected with Theileria annulata were collected from 10 townships in the County(Aqiang Township,Kalakeer Township,Koekya Township,Mugala Towns,Siyeke Township,Xianbaibazha Towns,Yingbage Township,Jiayi Township,Aoyituogelake Township,and Arixi Township).After extracting genomic DNA,PCR was performed to detect the Tams1 gene of bovine-derived Theileria annulata,and the number of positive samples and the positive rate of bovine-derived Theileria annulata were counted in the 10 townships.Then,among the townships where positive samples were found,two positive samples were randomly selected from each township for sequencing;the sequencing results were analyzed for homology and together with the reference sequences;an NJ phylogenetic tree was constructed to analyze the genotypes;finally,the genetic diversity of bovine-derived Theileria annulata populations in Yutian County was analyzed.The results showed that among 443 cattle blood samples,93 samples were positive,with a positive rate of 20.99%.Nine of the 10 townships were positive for bovine-derived Theileria annulata,with the positive rate ranging from 10.45%to 45.45%,with Aqiang Township having the highest positive rate.Jiayi Township were negative.The nucleotide similarity of the Tams1 gene sequences of the 18 strains of Theileria annulata ranged from 76.0%to 100%;the nucleotide similarity between two positive samples from the same township ranged from 91.0%to 100%.These 18 bovine-derived Theileria annulata were not all clustered into a single branch in the NJ phylogenetic tree,and some strains even showed closer affinity to other domestic and foreign reference strains,but all were the G1 genotype.The number of polymorphic loci in the G1 genotyped Theileria annulata populations in Yutian County was 119;the nucleotide diversity was 0.053;the average number of nucleotide differences was 28.95;the number of haplotypes was 12;and the haplotype diversity was 0.895.Tajima’s D value and Fu and Li’s F value were both less than 0.The results suggested that G1 genotyped Theileria annulata populations in Yutian County had high genetic diversity and was expanding.