Microsatellite diversity of Kessler’s loach, Paraschistura kessleri (Nemacheilidae), Gunther, 1889) in Khorasan Razavi

To study genetic structure of Paraschistura kessleri, a freshwater endemic species of Iran, 84 samples were collected from Kardeh, Zavin and Radkan rivers in Razavi Khorasan province and investigated with six microsatellite loci. Results indicated that Kessler's loach have proper allelic diversity (average: 9.16) and heterozygosity (average: 0.65) in studied regions. Only 4 of 18 loci-population tests were in Hardy-Weinberg equilibrium. The values of Fst and Rst as genetic differentiation indices were obtained 0.034 and 0.061, respectively. In this regard, the relatively high rate of gene flow, Nm: 7.28 could be considered as an important factor involved in low genetic differentiation obtained among the samples of investigated rivers. Also, the observed gene flow could be related to some factors including pollution, floods and life history of Kessler's loach. Results from analysis of molecular variance showed the majority of observed diversity is within populations. The highest genetic identity and distance values were observed among the samples of Radkan with Kardeh and Zavin with Radkan, respectively. Also, UPGMA dendrogram based on genetic distance showed that there are probably two separate populations of Kessler's loach in the investigated regions as Zavin was in a branch separate from Kardeh and Radkan.