investigation in genetical diversity are an effective tools for conservation of valuable, rare and endangered species. up until now, few studies have been conducted on the ecology of freshwater crabs in Iran and so their conservation issues are not fully known. This study aimed to assess the genetic diversity of the true crab, Potamon elbursi, from the eastern lakes of Tehran.
Material and methods:
The genetic structure of P. elbursi crab was investigated from the eastern rivers of Tehran Province using microsatellite markers. In order to study the genetic diversity within populations, 10 samples were caught with hand-operated net in different parts of Jajroud, Hablehrood and Lar rivers. Samples were first assessed for morphological variations using appropriate keys. Molecular identification of species was performed by COI gene sequencing. Then, the characterization of microsatellite loci (i.e., hxx3, Gagt4, Ga1, Ga2, and hxx2) was done using primers from Longpotamon yangtsekiense. Allelic abundance, expected/ observed heterozygosity, true alleles abundance, and genetic diversity were assessed using AMOVA at p= 0.01 level. Using images of the stained polyacrylamide gel, the molecular weight of the PCR product bands and the size of alleles were measured using Lab Image v.3.3.3 software. The allele frequency, expected and observed heterozygosity, number of actual and effective alleles in microsatellite loci, genetic diversity, and AMOVA test were calculated at 0.01 probability level in Gene Alex software. The MEGA software v.5.5 was used for plotting the phylogenetic tree.
Results and discussion:
The results showed that the COI sequences of all specimens were identical with those of P. elbursi, which was also confirmed by morphological analysis. The hxx2 and Ga1 positions with 7 alleles and Gagt4 with 3 alleles had the highest and lowest allele number among all heterozygote sites, respectively. The results also showed that the populations of this crayfish had a small intrinsic diversity.The observed and expected heterozygosity among the sampling stations at tetrad loci ranged from 0.100 to 0.51 and 0/81. 0.515-0.810, respectively.
Molecular identification methods may be useful for finding the exact lineage of the species and confirming morphological identification methods. In this study, in all samples from all locations and all loci, the observed heterozygosity was lower than the expected heterozygosity.