Mitochondrial DNA Lineages of Eurasian Otters (Lutra lutra) in Central Anatolia: A Phylogenetic Bridge Between Asia and Europe?

The Eurasian otter (Lutra lutra), a semi-aquatic carnivore listed as “Near Threatened” by the IUCN (International Union for Conservation of Nature), is widespread across Eurasia but remains poorly studied genetically in various regions. We analyzed the Central Anatolian population along the Kızılırmak River using mitochondrial (mt) DNA from non-invasively collected samples to examine whether Anatolian otters connect phylogenetically typical European and Caucasian lineages and whether Anatolia could have harbored a late-glacial source population for otter migration to Europe via western (Balkan) and/or eastern (east of the Black Sea) routes. Thirty spraints were collected from five localities, including four previously known sites and one newly identified in the Sulakyurt district, northeast of Kırıkkale province. We amplified a short (256 bp) mtD-loop fragment and a longer (820 bp) fragment spanning the Cytb, tRNA-Thr, tRNA-Pro, and D-loop from 14 samples and included all corresponding Lutra lutra mtDNA sequences available in GenBank in our analyses. Six short-fragment samples from Kapulukaya, Kesikköprü, and Kalecik carried the widespread northern Eurasian haplotype Lut1, while eight samples from Kalecik, Kesikköprü, Hirfanlı, and Hamzalı revealed a novel haplotype (H256-TR). The long fragments represented two additional haplotypes (H820-37, H820-38), distributed across the same localities. Median-joining network analysis of the short fragment produced a star-like topology with no clear phylogeographic structuring, whereas the longer fragment resolved two weakly separated phylogenetic groups. Central Anatolian haplotypes were positioned between Far Eastern and northern Eurasian lineages, with H820-38 phylogenetically connecting Caucasian and European haplotypes. This finding is consistent with the hypothesis of possible western and eastern postglacial migration routes from Anatolia to Europe, although broader spatial sampling is needed for confirmation.