Genetic Characterization of Nematodirella cameli Based on 18S rDNA and Cytochrome c Oxidase Subunit 1 (CO1)

To determine the phylogenic position and genetic diversity of Nematodirella cameli two portions of nuclear ribosomal DNA, 18S rDNA and mitochondrial DNA gene, the subunit 1 of cytochrome C oxidase gene (CO1) were sequenced and compared with those previously reported for other nematodes in Trichostrongylina. The phylogenetic trees constructed based upon the 18S rDNA sequences, yielded strong support for close relationship between the N. cameli and Nematodirus battus, with a high bootstrap value of 100%. In the present research, the level of sequence polymorphism among N. cameli isolates was higher for CO1 with 32 polymorphic sites compared to 18S rDNA sequence. Accordingly, molecular assays based on CO1 mitochondrial marker, demonstrated the existence of at least 11 distinct haplotypes (accession nos. JX305966 to JX305976) with an intraspecific diversity of 3-7% in Iran. Whereas, all of N. cameli samples examined herein (n=11), had a unique 18S sequence (accession no. JX305977). In addition, N. cameli CO1 sequences found in this study showed maximum identities to Haemonchus (88%) and Ostertagia (87%) in BLAST analysis for existing Trichostrongylina sequences. Further information is necessary to infer interspecific and intraspecific phylogenetic relationships between genera and species in Trichostrongylina. This study describes for the first time the nuclear 18S rDNA and mitochondrial CO1 sequence data from Nematodirella cameli species.