The mitochondrial genomes of soft ticks have an arrangement of genes that has remained unchanged for over 400 million years

Abstract

There are two major groups of ticks: soft ticks and hard ticks. The hard ticks comprise the prostriate ticks and the metastriate ticks. The mitochondrial (mt) genomes of one species of prostriate tick and two species of metastriate ticks had been sequenced prior to our study. The prostriate tick has the ancestral arrangement of mt genes of arthropods, whereas the two metastriate ticks have rearrangements of eight genes and duplicate control regions. However, the arrangement of genes in the mt genomes of soft ticks had not been studied. We sequenced the mt genomes of two species of soft ticks, Carios capensis and Ornithodoros moubata, and a metastriate tick, Haemaphysalis flava. We found that the soft ticks have the ancestral arrangement of mt genes of arthropods, whereas the metastriate tick, H. flava, shares the rearrangements of mt genes and duplicate control regions with the other two metastriate ticks that have previously been studied. Our study indicates that gene rearrangements and duplicate control regions in mt genomes occurred once in the most recent common ancestor of metastriate ticks, whereas the ancestral arrangement of arthropods has remained unchanged for over 400 million years in the lineages leading to the soft ticks and the prostriate ticks.

Discrimination between Haemaphysalis longicornis and H. qinghaiensis based on the partial 16S rDNA and the second internal transcribed spacer (ITS-2)

“…Both methods produced clear evidence that H. qinghaiensis and H. longicornis were different species. For H. qinghaiensis, the most phylogenetically related species was H. flava (Shao et al 2004). The ITS-2 fragments of H. qinghaiensis, H. longicornis and Ha.…”

The mitochondrial genome of the predatory mite Metaseiulus occidentalis (Arthropoda: Chelicerata: Acari: Phytoseiidae) is unexpectedly large and contains several novel features

“…AJ493124) (Navajas et al, 2002) and the tick Ixodes holocyclus (AB075955) (Shao et al, 2004) were obtained and aligned. Degenerate primers were designed using conserved amino acid sequences (Table S1).…”

“…Recent molecular analyses 2004), two scorpions (Davila et al, 2005;Gantenbein et al, 2005), three soft ticks Shao et al, 2004), four prostriate hard ticks (Black and Roehrdanz, 1998;Shao et al, 2004Shao et al, , 2005a, three metastriate hard ticks (Black and Roehrdanz, 1998;Shao et al, 2004), one honeybee mite (Evans and Lopez, 2002;Navajas et al, 2002), and three chigger mites (Shao et al, 2005b(Shao et al, , 2006. Among the mite families, no phytoseiid mitochondrion has been completely sequenced.…”

Mitochondrial genome sequence of Unionicola foili (Acari: Unionicolidae): a unique gene order with implications for phylogenetic inference

“…Within the chelicerates, genome structure synapomorphies are relatively rare in some clades, including soft ticks (Shao et al 2004), but abundant in others, including spiders (Masta and Boore 2008) and the Trombidiformes mites (Van Leeuwen et al 2006;Shao et al 2005). Of the six species of Trombidiformes whose completed mitochondrial genomes have been submitted to GenBank, there are five unique gene orders.…”