Complete Mitochondrial Genome of Three Species of the Genus Microtus (Arvicolinae, Rodentia)

SIMPLE SUMMARY: The knowledge and analysis of mitochondrial genomes can be useful to answer some interesting questions about the biology of some species. This is the case of vole species that are characterized by unusual genetic features related to sex chromosomes and variation of their karyotypes. In this work, we describe the mitochondrial genomes of three emblematic vole species, demonstrating that they are highly conserved in the organization of their protein coding, transfer RNA and ribosomal RNA genes. In addition, we performed a detailed analysis of their control regions identifying several domains and conserved boxes related to mitochondrial DNA regulation. Finally, a phylogenetic analysis with the mitochondrial DNA confirmed the established phylogeny of the analyzed voles. ABSTRACT: The 65 species of the genus Microtus have unusual sex-related genetic features and a high rate of karyotype variation. However, only nine complete mitogenomes for these species are currently available. We describe the complete mitogenome sequences of three Microtus, which vary in length from 16,295 bp to 16,331 bp, contain 13 protein-coding genes (PCGs), two ribosomal RNA genes, 22 transfer RNA genes and a control region. The length of the 13 PCGs and the coded proteins is the same in all three species, and the start and stop codons are conserved. The non-coding regions include the L-strand origin of replication, with the same sequence of 35 bp, and the control region, which varies between 896 bp and 930 bp in length. The control region includes three domains (Domains I, II and III) with extended termination-associated sequences (ETAS-1 and ETAS-2) in Domain I. Domain II and Domain III include five (CSB-B, C, D, E and F) and three (CSB-1, CSB-2, and CSB-3) conserved sequence blocks, respectively. Phylogenetic reconstructions using the mitochondrial genomes of all the available Microtus species and one representative species from another genus of the Arvicolinae subfamily reproduced the established phylogenetic relationships for all the Arvicolinae genera that were analyzed.