The complete mitochondrial genome of the RR-B strain of swordtail (Xiphophorus helleri).

Background and aims. The swordtail (Xiphophorus helleri) has been used in studies of behavior, phylogenetics, genetics, physiology, cell biology, cancer research, and biomedicine. Mitochondrial DNA (mtDNA) studies are of pressing need in order to assess the population history of the species. Materials and method. In this study, we present the complete mtDNA genome sequence of two specimens: one from a RR-B strain, a 27-generation inbred line; and one non-selective swordtail with red eyes and red body color from the Guangzhou market, measuring 16,638 and 16,635bp, respectively. Results. The genome comprises 13 protein-coding genes, 22 tRNAs, two rRNAs and a major non-coding region. The comparison of the two specimens' mitogenomes revealed a relatively low number (57) of single nucleotide polymorphisms29 located in protein-coding genes, 11 in rRNA genes, six in tRNA genes, and six in the non-coding region. Conclusion. We present an important genetic resource for the RR-B strain of swordtails and swordtail species in general.