Contributions to the Mitochondrial Genetic Variation and Phylogeny of the Eurasian Otter (Lutra lutra)

Abstract The mitochondrial CYTB and COI markers of a road-killed Eurasian otter (Lutra lutra) specimen from western Türkiye were analyzed within a phylogenetic context. Given the high haplotype similarity to European and Russian lineages, the Turkish sample was evaluated alongside these respective geographic cohorts. Nucleotide diversity for both markers was found to be extremely low (Pi = 0.001–0.007). The CYTB-based genetic distance between the Turkish specimen and other European populations (United Kingdom, Norway, Denmark, Switzerland, Poland, and Russia) was negligible (d = 0.09%). Conversely, the genetic distance between the Turkish sample and Asian populations was estimated at 0.8%. In contrast to the CYTB findings, the genetic diversity values of the COI marker were higher in the European population compared to the Asian population. The A–T content exceeded 50% for both markers, and the non-synonymous to synonymous substitution rate ratio (Ka/Ks) was greater than 1. Furthermore, in the constructed Median-joining network, the haplotypes of the Turkish sample clustered within the dominant haplogroups of the CYTB and COI markers, identified as H4 and H1, respectively.