Genetic analysis of population structure of alien North American mud crab Rhithropanopeus harrisii (Gould, 1841) in the Black Sea–Caspian region

Abstract

The structure of a fragment (523 nucleotide pairs) of the 1st subunit of mitochondrial cytochrome oxidase (COI) gene has been studied in the populations of alien crab Rhithropanopeus 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 common 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 Sea–Caspian region populations (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 Sea–Caspian 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 northeastern Black Sea might be partly isolated since their haplotype composition is slightly different from other populations in the region.