Analysis of sequence divergence in redfin (Cypriniformes, Cyprinidae, Tribolodon) based on mtDNA and nDNA markers with inferences in systematics and genetics of speciation

To clarify relationship of species of the genus Tribolodon in the Russian part of their distribution ranges, two mitochondrial markers (Co-1 and Cyt-b), a nuclear marker (Rho), and a gene marker of rDNA internal transcribed spacer (ITS-1,2) were used. Depending on the marker, different numbers of species groups were detected by the ABGD method, but in combination with the analysis of phylograms, these data generally support the known species clusters and regional intraspecies groups. A complex analysis of sequences from three redfin species within the area of the study, based on four marker genes and using the methods of molecular phylogenetics, ordination of genetic distances, recombinant analysis, and population genetic approaches, has revealed clusters of three commonly recognized species, regional intraspecific groups or individuals of local populations, and few hybrid individuals. DNA barcoding technique proved to be efficient with the use of two mtDNA markers: Co-1 and Cyt-b. It has been found that analysis of insertions and substitutions within the ITS-1,2 gene marker is also suitable for identification of Tribolodon species. Results of the studies of local groups do not confirm a sufficient level of differences for defining any new taxa of a species rank in the genus Tribolodon.