Mitogenome Characterization and Phylogenetic Insights Into Blind Mole Rats, Nannospalax nehringi, and N. turcicus,...

Blind mole rats (BMRs) are subterranean rodents adapted to hypoxic environments and increasingly recognized as biomedical models. In this study, the complete mitochondrial genomes of Nannospalax turcicus (16,421 bp) and N. nehringi (16,424 bp) were sequenced and analyzed phylogenetically. Both mitogenomes displayed conserved gene content and order. Phylogenetic relationships within the family Spalacidae were inferred using mitochondrial genomes. Bayesian and Maximum Likelihood analyses produced congruent topologies supporting subfamily monophyly. Codon usage-based clustering yielded a dendrogram consistent with the phylogenetic tree topologies. N. turcicus and N. nehringi formed a well-supported monophyletic clade, clearly separated from other Nannospalax species. Genetic divergences between N. nehringi and N. turcicus were 9.26% and 11.77% based on mitogenomic and cytochrome b (CYTB) data, respectively. CYTB sequence comparisons revealed low divergence (0.75%) within the Thracian N. leucodon populations, whereas a notably higher divergence (4.6%) was observed between these and the Çanakkale specimens currently annotated as N. turcicus, indicating marked regional genetic structuring across the Bosphorus/Dardanelles barrier. Additionally, genetic divergence between two N. nehringi samples from Kars was 1.96%. CYTB sequence analysis, a clear mitochondrial divergence was observed between N. turcicus specimens and N. leucodon specimens, indicating possible genetic differentiation between the BMR populations within the Turkish Thrace region. These findings highlight substantial mitochondrial differentiation and emphasize the need for broader sampling and integrative taxonomic approaches.