GENETIC ANALYSIS OF POPULATION STRUCTURE OF INVASIVE NORTH AMERICAN MUD CRAB <i>RHITHROPANOPEUSHARRISII</i> (GOULD, 1841) IN THE BLACK SEA - CASPIAN REGION
The structure of a fragment (523 nucleotide pairs) of the gene of the 1<sup>st</sup> subunit of mitochondrial cytochrome oxidase (COI) has been studied in the populations of invasive crab R. harrisii (family Panopeidae) that established in the basins of the Azov-Black and Caspian seas in 1930-1950s. In the samples of 6 populations from this region, 4 haplotypes (A, B, T, Lerm1) have been found. One of them has been unique (Lerm1) to the northern part of the Black Sea. Haplotype T has only been found in the Black and Caspian seas region, while haplotype A is found in almost all European populations. Only 4 substitutions have been observed in the sampled sequence, one of which is non-synonymous and there have been 3 polymorphic sites. The diversity of haplotypes (h) of the Black/Caspian seas region population (from 0.181±0.143 to 0.475±0.098) is significantly lower than this in the other European populations, where the value of h ranged from 0.563±0.063 to 0.795±0.065, and in North American populations (from 0.725±0.083 to ± 1 0). Harris crab populations of the Black/Caspian seas region have a common origin, and differ in their genetic structure from populations of the rest of introduction area in Europe. The population of the Caspian Sea originates directly from the Sea of Azov populations and, possibly, there have been numerously repeated exchange events due to shipping vector. The populations in the estuaries of rivers Shapsuho and Vulan in the north-eastern Black Sea might be isolated since their haplotype composition is slightly different from other populations in the region.