[Genetic variation of the mtDNA cyt b locus in topmouth gudgeon introduced into water bodies in the northern part of the Black Sea region].

The up-to-date phylogeographical distribution of the topmouth gudgeon Pseudorasbora parva Temminck et Schlegel 1846 in water bodies of the Northern Black Sea region is considered. Genetic variation of mtDNA cyt b gene is analyzed. It is established that topmouth gudgeon penetrated and spread in the basins of the Dnieper and Don rivers and in water bodies of Crimea from the secondary center of its dispersion­ water bodies of Central Europe. It is demonstrated that haplotypes of topmouth gudgeon in the Danube delta are the most homologous to the haplotypes in the native range of the species in China. A considerable decrease in the level of genetic variation in the populations in the Black Sea region is reported.

[Genetic Variation of the mtDNA cyt b Locus in Graylings (Thymalus sp.: Thymalidae, Pisces) Introduced into the Baydrag Gol River of the Valley of Lakes Basin (Mongolia)].

Based on sequence variation of the mtDNA cyt b gene, an analysis of graylings introduced from the Arctic Ocean basin (Selenga River basin) into one of the rivers of Central Asian inland basin (Baydrag Goal River of the Valley of Lakes basin) was carried out. Morphological and molecular genetic identification was performed, and it was established that the introduced species corresponded to the Baikal grayling. The relationships among Central Asian grayling species are discussed.

[Phylogeography and phenotypic diversity of the pumpkinseed Sunfish Lepomis gibbosus (Linnaeus, 1758) of the Northern Black Sea Coast].

This paper studies the origin and the genetic and morphological diversity of the pumpkinseed sunfish, a North American invader that is actively expanding its range in the Northern Black Sea Coast. Based on an analysis of variability of the nucleotide sequence of the mtDNA cyt b locus, it was found that all populations of the Northern Black Sea Coast (basins of Dnieper, Dniester, and Danube rivers) are represented by one haplotype. Intraspecific variability is absent. Phylogeographic analysis revealed that the most related haplotype is in a population of pumpkinseed sunfish from New Germany Lake in the Potomac Riverbasin (Maryland, United States), which makes it possible to consider it a parent of the investigated populations. Morphological variation oin countable traits was highly homogeneous. Significant differentiation of a sample from the population of the Dnieper Reservoir from the populations of the Danube and Dniester was found for plastic traits of both the body and cranium. Analysis of the trajectories of development showed that the Dnieper is inhabited by a "pelagic" morpho-ecological form of pumpkinseed sunfish, while the Dniester and Danube is inhabited by a "littoral" form. It is suggested that the success of the settlement of this North American species in the Northern Black Sea Coast does not depend on the origin or the level of its genetic diversity but is instead likely to be ensured by the realization of its available discrete morpho-ecological variability.

[Haplotype diversity in the mtDNA cyt b gene in round goby (Neogobius melanostomus (Pallas)) from the Northwestern part of the Black Sea Basin].

To study the genetic causes of successful biological invasion, haplotype diversity in the mtDNA cyt b locus was examined in populations of the round goby (Neogobius malanostomus (Pallas): (Gobidae, Piscs) from the Black Sea basin, which is considered tobe the main source of irruption. It was demonstrated that the haplotype diversity of this species was much higher than was assessed earlier. At the population level, a statistically significant association of haplotype diversity with the individual variation of plastic characters was established.

[Phylogeography and origin of freshwater Populations of tubenose gobies of genus Proterorhinus (Gobiidae: Pisces) in Ponto-Caspian Basin].

Representatives of the genus Proterorhinus (tubenose gobies) from the water bodies of the Ponto-Caspian Basin were examined for sequence polymorphism of the mitochondrial DNA fragment containing the cytochrome b (Cyt-b) gene. A total often haplotypes were discovered, which formed two groups. Thus, the data obtained indicated the existence of only two taxonomically valid phylogenetic lineages, represented by (1) marine and brackish-water populations of the Black Sea and (2) freshwater populations of the whole Ponto-Caspian Basin, along with the brackish-water population of the Caspian Sea. Based on an analysis of the tubenose goby haplotype distribution patterns, the colonization patterns of this group of fishes (phylogeography) in the freshwater drainages of Ponto-Caspian Basin are examined. It was established that the basin of the ancient Caspian Sea was the major donor area for the formation of the freshwater and brackish-water populations. In the Ponto-Caspian Basin, two centers of the tubenose gobies speciation and distribution are distinguished. One of these centers is associated with the modern northwestern part of the Black Sea, and another one is confined to the Caspian Sea. It is suggested that the modern colonization of the Volga River by tubenose goby occurred from the Caspian Sea.