Comparative analysis of the mitochondrial genomes in Drosophila virilis species group (Diptera: Drosophilidae)

Abstract

We present comparative analysis of mitogenomicsdata of the Drosophila virilis groupbased on newly obtained complete mt-genomesequence of Drosophila littoralis, previouslypublished mt-genome sequence of D. virilisand fragments of mt-genomes of otherDrosophila species belonging to the virilisgroup. Drosophila of the virilis group sharedmost recent common ancestry 40 MYA with D.melanogaster. Therefore, presented data helpto overview the evolution of the genus. The mtgenomeof D. littoralis is a circular molecule of16,017 bp with a total A+T content of 76.2%.The gene order is consistent with otherDrosophila genomes. All tRNAs can be foldedin the form of a typical clover-leaf structureexcept for tRNASer(AGN). In the control regionof D. littoralis we found four conservedsequence elements: 275 bp highly conservedsequence element, two thymidylate stretchesand a G-island. The most variable genes inDrosophila of the virilis group are nad6, nad3and nad4L. The most conservative is cox1. Werevealed long intergenic sequences' (TA) n separatingatp6 and cox3 genes in the mitochondrialgenomes of Drosophila of the virilisgroup. In other insect species these geneshave no or few separating nucleotides. Wedetected fragments of mitochondrial genesatp6 and cox3 in the nuclear genome of D. virilis.These mitochondrial pseudogenes aremarked by site-specific insertions of Tv1 retrotransposonin the (TA) n intergenic spacersequences. © B. Andrianov et al., 2010 Licensee PAGEPress, Italy.