Microsatellite diversity and population genetic structure of Squalidus argentatus (Cyprinidae) on the Island of Hainan and mainland China

Squalidus argentatus is a small-sized cyprinid fish and widely distributed in mainland China. A total of nine polymorphic microsatellite markers were employed to study 216 individuals collected from nine populations. The average number of alleles among nine populations was 8.0 with a range from 6.5 to 9.7. The mean observed (H_O) and expected (H_E) heterozygosity ranged from 0.56 to 0.68 and from 0.74 to 0.86, respectively. The analysis of molecular variance (AMOVA) showed that most genetic variation was maintained within individual component, rather than shaped according to geographical regions. Small but highly significant values of pairwise F_ST values were detected among nine populations. The genetic homoplasy and overfishing are supposed to be major factors responsible for the current genetic structure. This study can be not only helpful for sustainable management of genetic resources, but also valuable to demonstrate genetically how freshwater species is vulnerable to human activity.