Nucleotide sequence diversity of the mitochondrial cytochrome oxidase subunit I (COI) gene of the Arctic lamprey (Lethenteron camtschaticum) in the Eurasian part of the range

The taxonomy and nomenclature of residential and anadromous forms of lampreys of the genus Lethenteron are still debated. For this reason, the distribution of mtDNA COI partial sequence haplotypes of lamprey (genus Lethenteron) in Eurasia has been studied. Many haplotypes occur throughout the genus range, their frequencies varying in different regions. Both rare haplotypes, some of them specific for particular geographic regions, and common ones have been found. The haplotype occurrences do not exhibit correlation with the life history strategy of their carriers. The first data on heteroplasmy in lampreys have been obtained. The results obtained and recent published data on the morphology and biology of Lethenteron indicate that the neither the region of habitat nor the life history can serve as criteria for species identification of these animals. We suggest that the residential lampreys described as separate species L. reissneri and L. kessleri should be regarded as ecological forms of L. camtschaticum, which was initially described as an anadromous parasitic species.