Vendace (Coregonus albula) and least cisco (Coregonus sardinella) are a single species: evidence from revised data on mitochondrial and nuclear DNA polymorphism

This study elucidates the phylogenetic relationships of three coregonid species: the vendace (Coregonus albula), least cisco (Coregonus sardinella), and peled (Coregonus peled). The nucleotide sequences of two mitochondrial DNA (mtDNA) regions, subunit I of the NADH dehydrogenase gene (nd1, 975 bp) and a fragment of the cytochrome oxidase subunit I gene (co1, 527 bp), were studied in representatives of these species from different populations. In addition, the polymorphism of a fragment of nuclear recombination-activating gene 1 (rag1, 1093 bp) was investigated. The species were not differentiated with respect to the co1 sequence, and a species-specific nucleotide substitution in the rag1 sequence was found in the peled. Phylogenetic analysis of the nd1 sequences confirmed that C. albula and C. sardinella are actually a single Eurasian species, C. albula, with European and Siberian populations being polyphyletic groups. The peled is closely related to the vendace and least cisco is apparently a separate monophyletic species that is poorly differentiated from C. albula. According to published data, reproductive isolation of the peled was determined by chromosome rearrangements that led to a change in the system of sex determination rather than by the accumulation of nucleotide substitutions.

Automated summary

This study revealed the phylogenetic relationships of three coregonid species: vendace, least cisco, and peled, based on nucleotide sequences analysis. The results showed that C. albula and C. sardinella are actually a single species, while peled is closely related to vendace. The reproductive isolation of peled was determined by chromosome rearrangements rather than nucleotide substitutions.