Comparative analyses of the complete mitochondrial genomes of Cyathostomum pateratum and Cyathostomum catinatum provide new molecular data for the evolution of Cyathostominae nematodes

Abstract

The parasite Cyathostomum pateratum, which occurs in the large intestine of equines, is a common species of the subfamily Cyathostominae. Cyathostominae nematodes are a complex nematode group for which only limited genetic information has been reported. To re-examine the phylogenetic relationships among Cyathostominae nematodes, we sequenced the complete mitochondrial (mt) genome of Cy. pateratum and compared it with the mt genome of the congeneric species Cyathostomum catinatum. The complete mtDNA sequence of Cy. pateratum was 13,822 bp in length, 16 bp shorter than that of Cy. catinatum. The mtDNA sequences of both species contained 12 protein-coding genes, two rRNA genes and 22 tRNA genes, and all 36 genes were transcribed in the same direction and in the same strand. Pairwise comparisons of the 12 predicted amino acid sequences between Cy. catinatum and Cy. pateratum revealed differences of 0.4-3.1%; the least conserved sequence was that of cytochrome c oxidase subunit 3 (cox3). Phylogenetic analysis of the concatenated amino acid sequences using Bayesian inference and maximum likelihood methods showed that Cy. catinatum and Cy. pateratum clustered together with very high nodal support, and Cylicostephanus goldi was closer to the Cyathostomum nematodes than to other Cyathostominae nematodes. The mtDNA sequence of Cy. pateratum is reported here for the first time. The study will shed some light on the genetic evolution among parasitic nematodes in Cyathostomum.

The Mitochondrial Genome of Cylicocyclus elongatus (Strongylida: Strongylidae) and Its Comparative Analysis with Other Cylicocyclus Species

“…Comparison of nucleotide and amino acid sequences of mt genomes among six Cylicocyclus species and P. imparidentatum was performed. In previous studies, the identities of nucleotide sequences of complete mt genomes in congeners were 94.6% identity between Cyathostomum pateratum and Cyathostomum catinatum , 84.7% identity between Chabertia ovina and Chabertia erschowi , and 86.0% identity between Triodontophorus serratus and Triodontophorus nipponicus , respectively [ 22 , 23 , 24 ]. In the present study, C. elongatus had higher identities to congeneric nematodes rather than to P. imparidentatum , indicating that C. elongatus was more similar to Cylicocyclus species in terms of nucleotide sequences [ 11 , 14 , 16 ].…”

Comparative mitogenomics of Spirocerca lupi from South Africa and China: Variation and possible heteroplasmy

“…Mitochondrial genomes have become important in clinical diagnosis as mutations contribute to neurodegeneration as well as other mitochondrial diseases (Kennedy et al, 2012;Tavares and Seuánez, 2017). Complete mitochondrial sequences have been used extensively in phylogenetic and diversity studies of parasitic nematodes (Park et al, 2011;Qiu et al, 2018;Yilmaz et al, 2016).…”