关键词: 狮弓蛔虫, pnad5, pnad1, 狐狸, 犬, 遗传变异

Abstract: 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 0.0342, 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. Conclusion　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.

Key words: Toxascaris leonina, pnad5, pnad1, Fox, Dog, Genetic variation