Abstract
To investigate the germplasm differences between northern and southern populations of Parabramis pekinensis and analyze their genetic diversity and population structure, this study employed 10 developed microsatellite markers to analyze 133 individuals collected from the Yangtze River Basin (Jiangsu JS, Hunan HN) and the Amur River Basin (Jilin JL, Heilongjiang HLJ). The HLJ population is considered a wild stock, while the other three groups are classified as cultured populations. The analysis revealed that four Parabramis pekinensis populations exhibited high levels of genetic diversity, with polymorphic information content (PIC) ranging from 0.5130 to 0.6142. A total of 249 alleles were detected, among which the HN population showed the highest genetic diversity (Na = 8.0 ± 4.59). The analysis of molecular variance (AMOVA) revealed significant genetic differentiation among populations, with 34% of gene variation attributed to inter-population differences (Fst = 0.337). The UPGMA clustering and STRUCTURE analysis (optimal K = 3) grouped the JL and HLJ populations into a single cluster, which subsequently merged with the JS population to form a larger clade. In contrast, the HN population was distinctly separated as an independent branch. The study demonstrates that the HN population of P. pekinensis should be prioritized for conservation as a distinct genetic unit, with the enhancement of habitat connectivity among northern populations could effectively mitigate genetic diversity loss. These findings provide a scientific foundation for the preservation of P. pekinensis germplasm resources.