The mitochondrial genome of Protostrongylus rufescens – implications for population and systematic studies

BACKGROUND: Protostrongylus rufescens is a metastrongyloid nematode of small ruminants, such as sheep and goats, causing protostrongylosis. In spite of its importance, the ecology and epidemiology of this parasite are not entirely understood. In addition, genetic data are scant for P. rufescens and related metastrongyloids. METHODS: The mt genome was amplified from a single adult worm of P. rufescens (from sheep) by long-PCR, sequenced using 454-technology and annotated using bioinformatic tools. Amino acid sequences inferred from individual genes of the mt genomes were concatenated and subjected to phylogenetic analysis using Bayesian inference. RESULTS: The circular mitochondrial genome was 13,619 bp in length and contained two ribosomal RNA, 12 protein-coding and 22 transfer RNA genes, consistent with nematodes of the order Strongylida for which mt genomes have been determined. Phylogenetic analysis of the concatenated amino acid sequence data for the 12 mt proteins showed that P. rufescens was closely related to Aelurostrongylus abstrusus, Angiostrongylus vasorum, Angiostrongylus cantonensis and Angiostrongylus costaricensis. CONCLUSIONS: The mt genome determined herein provides a source of markers for future investigations of P. rufescens. Molecular tools, employing such mt markers, are likely to find applicability in studies of the population biology of this parasite and the systematics of lungworms.