Comparison of seven complete mitochondrial genomes from Lamprologus and Neolamprologus (Chordata, Teleostei, Perciformes) and the phylogenetic implications for Cichlidae

Abstract

In this study, mitochondrial genomes (mitogenomes) of seven cichlid species (Lamprologus kungweensis, L. meleagris, L. ornatipinnis, Neolamprologus brevis, N. caudopunctatus, N. leleupi, and N. similis) are characterized for the first time. The newly sequenced mitogenomes contained 37 typical genes [13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs) and 22 transfer RNA genes (tRNAs)]. The mitogenomes were 16,562 ~ 16,587 bp in length with an A + T composition of 52.1~58.8%. The cichlid mitogenomes had a comparable nucleotide composition, A + T content was higher than the G + C content. The AT-skews of most mitogenomes were inconspicuously positive and the GC-skews were negative, indicating higher occurrences of C than G. Most PCGs started with the conventional start codon, ATN. There was no essential difference in the codon usage patterns of these seven species. Using Ka/Ks, we found the fastest-evolving gene were atp8. But the results of p-distance indicated that the fastest-evolving gene was nad6. Phylogenetic analysis revealed that L. meleagris did not cluster with Lamprologus species, but with species from the genus Neolamprologus. The novel information obtained about these mitogenomes will contribute to elucidating the complex relationships among cichlid species.