Characterization of a translocated Mitochondrial Cytochrome b pseudogene in Meriones persicus (Rodentia; Gerbillinae); a potential taxonomic pitfall

Due to its faster evolution rate compared to nuclear genes, haploid mitochondrial DNA (mtDNA) is a promising species identification tool. This has led to its significant use in taxonomic and phylogenetic studies. While mtDNA is subject to selective constraints that prevent the accumulation of deleterious mutations, the prevalence of nuclear-mitochondrial fragments (known as NUMTs or pseudogenes) in mammals has complicated the use of mtDNA for taxonomy. In the present study, a pseudogene of the mitochondrial cytochrome b (Cytb) was detected in Meriones persicus. This pseudogene differed from its mitochondrial counterpart at 235 out of 1140 sites, and is characterized by frame-shift mutations, indels, and accumulation of non-synonymous substitutions. It is the first report of the Cytb pseudogene in a jird, highlighting the risk of misidentifying NUMTs as authentic mtDNA and the importance of addressing this potential pitfall in taxonomic studies.