Genetic characterization of Garra rufa (Heckel, 1843) populations in Tigris Basin, Iran using microsatellite markers

The isolation-by-distance theory states that the genetic differentiation between individuals raised by increasing geographic distance. Therefore, this study tested this hypothesis for Garra rufa, a freshwater fish species of Iranian inland waters, from six rivers located at the different distances in Tirgis basin. For this purpose, eight variable microsatellite loci were applied to identify geographic-based population structure of G. rufa. From 240 fish of six populations, 102 alleles were found with a mean number of 11.625 to 13.250 alleles. Heterozygosity was ranged 0.567-0.638 in six studied populations. Moreover, a significant deviations from Hardy-Weinberg were found in the studied populations. Unweight pair group analysis indicated that the six studied populations could be divided into four major clusters. The results revealed a fairly high level of genetic variation in the microsatellite loci within six studied populations. Wright’s fixation index (Fst) ranged between 0.013-0.044 indicating little genetic differentiation between populations. Within this range, however, we found a strong positive relation between Fst and geographical distance lending support to the isolation-by-distance theory.