关键词: 旋毛虫, 5S rDNA 基因, 分离株

Abstract: 【Abstract】 Objective To analyze 5S ribosomal DNA （5S rDNA） sequences of two Trichinella isolates from Guangxi. Methods The fragments of 5S rDNA were obtained by PCR from the isolates of Debao and Nandan， and sequencing was made for the PCR products. Homogeneity， genetic distance matrix and phylogenetic tree were analyzed by related software. 5S rDNA sequences of the two isolates were compared separately with those of Trichinella species in GenBank. Results 5S rDNA sequences of three Trichinella isolates （Debao， Nandan and T.spiralis） showed the same length at 695 bp. There were 4 variable positions. The homogeneities of Debao and Nandan isolates with T.spiralis were 99.0% and 99.1% respectively. The homogeneities between Debao isolate and Nandan isolate was 98.8%. Compared with other Trichinella isolates in GenBank， they were all less than 94.2%. The evolutionary distance among isolates of Debao and Nandan and T.spiralis was 0.014. Meanwhile， the evolutionary distances between the Guangxi isolates and other Trichinella isolates in GenBank were more than 0.056. Phylogenetic tree analysis revealed that two isolates of Guangxi and T.spiralis located at the same node， revealing a close relationship. Bootstrap confidence values in two phylogenetic trees were 96 and 99， respectively. Conclusion The two Trichinella isolates of Guangxi show a high homogeneity with T.spiralis，locate at the same nodes in phylogenetic tree，suggesting that the Debao and Nandan Trichinella isolates be identified as T.spiralis.

Key words: Trichinella spiralis, 5S rDNA gene, Isolate