Determination of genetic diversity in Turkish crayfish (pontastacus leptodactylus eschscholtz, 1823) populations using microsatellite markers

In Turkey, the crayfish is represented with two crayfish species. The first one is stone crayfish (Astropotamobius terrentium) which is distributed in Trace Region of country and the second one is narrow clawed crayfish or Turkish crayfish (Pontastacus leptodactylus) which is distrubuted country wide. As a result of the crayfish plague in 1984, Turkish crayfish stocks were affected daramatically and many natural stocks were faced with threat of extinction due to this disease. It is very important to reveal the genetic structure of existing populations which are under risk in order to determine new strategies for conserving these crayfish stocks. Therefore, we aimed to determine the genetic diversity parameters between and within important Turkish crayfish populations distrubuted in contry waters and obtain genetic information about this species. In this PhD study, a total of 220 crayfish specimens from 11 important crayfish populations were genotyped using 10 microsatellite markers. A total of 172 alleles were obtained and the number of alleles were varied between 4 and 44 according to the loci. The results obtained from all studied populations shoved that the observed heterozygosity was ranged between 0.046-0.854, and the expected heterozygosity was ranged between 0.054-0.901. The gene flow (Nm) value was calculated as 0.839. It has been determined that 21.96% of the total genetic diversity originates from the differences between the populations, 22.83% from the individuals within the populations, and 55.21% from the differences among all individuals. Considering the genetic structure of the studied populations, it was determined that there was a gene flow between all populations except Çıldır Lake and Bafra Balık Lakes. Genetic structure of Turkish narrow clawed crayfish populations was investigated for the first time with the SSR marker in this PhD thesis. The obtained data provided important information related to the genetic diversity of narrow clawed crayfish populations in Turkey. It is thought that this information will support the breeding and breeding studies about crayfish besides genetic conservation and management of important crayfish populations.