Microsatellite diversity and population genetic structure of yellowcheek, Elopichthys bambusa (Cyprinidae) in the Yangtze River

Yellowcheek carp (Elopichthys bambusa) is the only species of genus Elopichthys. It is widely distributed in Chinese freshwaters but currently its populations have declined to threatening level. We examined the genetic diversity and population structure of E. bambusa in the Yangtze River basin. A total of nine polymorphic microsatellite markers were employed to study five populations occurring in middle and lower reaches of the river. The results revealed low-to-moderate genetic diversity. The number of alleles per locus varied between 3 and 8 with an average of 4.8. Observed heterozygosity ranged from 0.15 to a maximum of 1.00. Significant deviations (P < 0.01) from Hardy–Weinberg equilibrium were observed for all the tested locus-population combinations with clear heterozygosity deficits. AMOVA indicated that majority of the variance lies within populations (93.81%) than among the populations (7.05%). Pairwise F_ST and unbiased genetic distance pointed out significant differentiation among the samples from populations with different connections to the Yangtze River. In the UPGMA dendrogram, clustering pattern of populations indicated that most of the populations are reproductively isolated due to anthropogenic interventions. Clustering of PYL and DTL populations shows ongoing gene flow through the mainstream. The recent hydrological alterations and overfishing are major factors shaping the current genetic structure. These results can be helpful for effective management and sustainable conservation of E. bambusa populations.