Objective: To investigate the genetic variations of Toxascaris leonina isolates from different hosts in Jiuquan City, Gansu Province.
Methods: The mitochondrial sequences of partial mitochondrial nicotinamide adenine dinucleotide dehydrogenase subunit 1 (pnad1) and pnad5 of eleven T. leonina isolates from domestic dogs, foxes and pet dogs in Jiuquan City, Gansu Province, were amplified using PCR, and the amplification product was sequenced. The genetic variations of pnad1 and pnad5 genes in T. leonina isolates were analyzed.
Results: The sequences of T. leonina pnad1 and pnad5 genes measured 530 bp and 550 bp in size, respectively. The nucleotide sequence homology was 99.4% to 100.0% for T. leonina pnad1 gene and 99.5% to 99.8% for T. leonina pnad5 gene, and the sequences of T. leonina pnad1 and pnad5 genes shared 99.2% to 99.9% and 99.1% to 99.9% with corresponding sequences of known T. leonina isolates. In addition, there were 19 and 24 polymorphic sites detected in the sequences of T. leonina pnad1 and pnad5 genes, with 10 and 9 haplotypes, haplotype diversity of 0.982 and 0.964 and nucleotide diversity of 0.039 4 and 0.034 2, respectively. Phylogenetic analysis based on pnad1 and pnad5 gene sequences showed that the eleven T. leonina isolates and known T. leonina isolates were clustered into the same branch with a random distribution, which were close to the branch where Toxocara canis was clustered, and far from the branch where other Ascaris species were clustered.
Conclusions: There is a minor genetic variation in pnad1 and pnad5 genes of T. leonina isolates from different hosts in Jiuquan City, Gansu Province, and the pnad1 gene is more suitable as a molecular marker than pnad5 gene for analysis of genetic variations in T. leonina.
［摘要］ 目的探究甘肃省酒泉市不同宿主源狮弓蛔虫基因遗传变异。方法 应用PCR技术对甘肃省酒泉地区采集的 11株分离自家犬、狐狸和宠物犬的狮弓蛔虫分离株线粒体烟酰胺腺嘌呤二核苷酸脱氢酶第1亚基部分序列基因(partial nicotinamide adenine dinucleotide dehydrogenase subunit 1, pnad1)和烟酰胺腺嘌呤二核苷酸脱氢酶第5亚基部分序列基因 (partial nicotinamide adenine dinucleotide dehydrogenase subunit 5, pnad5)进行基因扩增, 并对 PCR 扩增产物进行测序, 分 析其遗传变异。结果 获得的犬源和狐狸源狮弓蛔虫分离株pnad1和pnad5基因序列大小分别为530 bp和550 bp, 不同 分离株间核苷酸序列同源性分别为99.4% ~ 100.0%和99.5% ~ 99.8%, 与已知狮弓蛔虫分离株对应序列同源性分别为 99.2% ~ 99.9%和99.1% ~ 99.9%;分别检测到19个和24个遗传变异位点, 单倍型分别为10和9个, 单倍型多样性分别为 0.982和0.964, 核苷酸多样性分别为0.039 4和0.034 2。基于两种基因序列构建的遗传进化树结果基本一致:11株不同 宿主分离株与已知狮弓蛔虫分离株位于同一分支, 且为随机分布;与犬弓首蛔虫所属分支相隔较近, 与其他蛔虫所属分 支相距较远。结论 甘肃省酒泉市不同宿主来源狮弓蛔虫分离株pnad1和pnad5基因遗传变异较小, pnad1基因较pnad5 基因更适合作为分子标记用于分析狮弓蛔虫遗传变异。.
Keywords:
Dog; Fox; Genetic variation;