Sequencing the complete mitochondrial genome of Eimeria mitis strain USDA 50 (Apicomplexa: Eimeriidae) suggests conserved start positions for mtCOI- and mtCOIII-coding regions

Four complete mitochondrial (mt) sequences from a single-oocyst-derived line of Eimeria mitis USDA 50 were obtained (three from cloned whole-genome PCR products, one from directly sequenced whole-genome PCR product). The mt genome is 6,408 bp long with three genes (CytB, cytochrome c oxidase subunit I (COI) and cytochrome c oxidase subunit III (COIII)) and many rDNA fragments (large subunit rDNA 13, small subunit rDNA 10); organisation was identical to other Eimeria sp. mt genomes. Conserved start codon positions for both COI and COIII are suggested for all Eimeria mt genomes; these start codon positions exist and may also be conserved, in related apicomplexan parasites. Within the three separate cloned PCR products of near-complete mt genomes, there were 26 nucleotide differences (collectively) compared to the directly sequenced mt genome. These changes appear to be base misincorporations during PCR. Direct sequencing of long PCR amplification products may be more likely to generate accurate mt genomic sequences than cloning and subsequent sequencing.