Occurrence of sympatric charr groups, Salvelinus, Salmonidae, in the lakes of Kamchatka: a legacy of the last glaciations.

Six postglacial lakes were studied along both sides of the Kamchatka central mountain range, Russia. Pairs of local morphotypes of species of Arctic charrs, Salvelinus spp., have previously been described from the southernmost lakes while the fish fauna of the four northernmost lakes was studied here for the first time. Phenotypic data support the division of Kamchatkan lacustrine charrs into two groups according to the number of gill rakers and pyloric caeca, as well as snout-dorsal and snout-ventral distances (MANOVA, P < 0·001). These groups respectively correspond to phenotypes commonly referred to as Salvelinus malma and Salvelinus taranetzi. To clarify the identity of these groups, D-loop and cytochrome b (cytb) region sequences were analysed. Haplotype network analysis of mtDNA shows the salmonids inhabiting four lakes on the south and north are phylogenetically close to either Beringian S. malma or to S. taranetzi from the Chukotka and Kolyma River basins (the mean ± s.e. pairwise per cent sequence divergence is 0·006 ± 0·001). Phenotype-genotype discordance suggests that mitochondrial introgression between species has occurred in the two smallest lakes (<0·5 km2 ) in the central part of the peninsula. Identical haplotypes of D-loop and cytb regions were found for the populations of S. taranetzi from the most distant southern and northern lakes, indicating all lakes were colonized by both species simultaneously after the last glacial maximum. Salvelinus taranetzi may have colonized the Kamchatka peninsula from one or both of two different source regions: the Arctic Beringia and the northern coast of the Okhotsk Sea.

[Genetic Differentiation of Balkhash Perch Perca schrenki Kessler, 1874 from Lake Balkhash and Alakol Lake System of Kazakhstan].

The genetic differentiation of two populations of Balkhash perch Perca schrenki Kessler, 1874 was examined. The study included (1) the population of Lake Balkhash and the Ili River delta, where this species is protected and it is prohibited to catch them and (2) the population of Alakol Lake system, where it is the main commercial species and forms two morphotypes--pelagic and coastal. Analysis of the mitochondrial DNA COI gene and. six microsatellite loci revealed genetic differentiation at the population level, while no statistically significant differences were found at the morphotype level. The results of this study make it possible with high probability to determine the belonging of caught fish to either the commercial (Alakol Lake system) or protected (Lake Balkhash) population.

Genetic differentiation of Pacific cod Gadus macrocephalus in the Sea of Okhotsk and in the Bering Sea.

Genetic differentiation of the Pacific cod Gadus macrocephalus was studied. Samples from six regions of the Sea of Okhotsk and the Bering Sea were analyzed with two mtDNA genetic markers-gene of cytochrome 1 and the control region (D-loop). Comparative analysis showed significant genetic differentiation between the two groups of samples. The first group included samples from Tauiskaya Bay and waters of Western Kamchatka. The second group consisted of the samples collected in the waters of the Iturup Island (Sea of Okhotsk), Northern Kurile Islands, Navarin region of the Bering Sea, and Anadyr Bay.

[Genetic variation at the pantophysin (PanI) locus in North-East Arctic cod Gadus morhua L. (Gadiformes: Gadidae) population in the Barents Sea and adjacent waters].

We investigated polymorphisms in the pantophysin gene (Pan I locus) in a population of North-East Arctic cod, Gadus morhua L., throughout its foraging area in the Barents Sea and adjacent waters. Correlations between the frequencies of Pan I alleles and habitat conditions, such as depth and temperature, were explored. This study was based on a large number of specimens (2210 individuals) of different age and wide geographic sampling coverage. The frequency of the Pan I(A) allele, a known genetic marker of coastal cod, varied from zero to 0.47. Allele frequencies correlated with depth at the sampling location but not with bottom water temperatures. We observed variations in Pan I(A) frequencies among different age cohorts from the same area. The most prominent shift in Pan I polymorphism was detected at the early stages of the fish life cycle, between pelagic juveniles and benthic cod. We found that the Pan I(A) allele frequency in pelagic yearling cod was essentially same throughout the studied areas in the Barents Sea. In turn, juveniles settling at the northern and deep water locations showed a significant decrease in the allele frequency. In contrast, the frequency of the Pan I(A) allele remained constant in juveniles settling in shallow waters when compared to the pelagic stage. These results confirm the selective nature of the cod Pan I locus and indicate that selection process acting on individuals with different genotypes at the Pan I locus leads to the formation of a stable spatial distribution of allele frequencies observed in adult cod.

[Genetic study of pike perch Sander lucioperca (Linnaeus, 1758) and bersh Sander volgensis (Gmelin, 1789) from the fishery water-bodies of Kazakhstan].

The genetic polymorphism of the pike perch Sander lucioperca, sampled on the territory of the Republic of Kazakhstan (Lake Balkhash, Urals River, Syrdarya River and Shardara water reservoir, North Aral Sea) and in the Volga River, and the bersh Sandler volgensis (Lake Balkhash, Volga River) populations was examined at six microsatellite loci and the mitochondrial DNA cytochirome b gene. All examined loci were successfully amplified in both species and produced quite different allele profiles, whichallows them to be used for accurate species identification of pike perch and bersh. At the same time, neither nuclear nor mitochondrial markers revealed statistically significant differentiation betweenthe examined pike perch samples, excluding some isolation of the population from Volga River.

[Large-scale genome duplications and paralog divergence in fish].

Based on fish genomic studies, we review mechanisms of divergence in duplicated genes (paralogs), resulted in small ("subfunctionalization") or large ("neofunctionalization") changes in paralogs. Gene divergence occurs due to several processes, such as non-synonymous substitutions, exon-intron structure rearrangement, and alterations in regulatory regions, which cause differential temporal or spatial expression of paralogous gene copies during ontogenesis.

[The use of microsatellite loci for identification of sturgeon species (Acipenseridae) and hybrid forms].

The genetic polymorphism often sturgeon species that inhabit the territory of the Russian Federation (Russian sturgeon, Siberian sturgeon, Amur sturgeon, Sakhalin sturgeon, Persian sturgeon, ship sturgeon, starlet, stellate sturgeon, beluga, and kaluga) was examined at five microsatellite loci (Afug41, Afug51, An20, AoxD161, AoxD165) (in total, 3821 individuals). The examined loci were successfully amplified with the same primer set in all species tested and demonstrated a high level of variation. Alleles specific to different species have been identified, which allows them to be used to identify species of sturgeon and their food products. In addition, the possibility of identifying hybrid forms was demonstrated. The assignment test performed in the STRUCTURE software program showed a high probability of correctly assigning each individual to its species based on genotyping with five microsatellite loci examined (96-98%, on average). However, for Russian and Persian sturgeon, the rate of proper species assignment was considerably lower (75 and 84%, respectively).