Researchers used ten microsatellite markers to evaluate the genetic structure of six populations from the Yangtze, Huaihe, and Ussuri River basins. The northern Ussuri population stood out for its lower diversity and significant genetic separation from southern populations.
Yellow catfish (Pelteobagrus fulvidraco) is a widely farmed freshwater fish species in China, prized for its high nutritional value and boneless flesh. Annual production exceeds 600,000 tons, making it a key species in China's aquaculture sector. However, challenges such as slow growth rates and marked sexual dimorphism—where males grow faster than females—affect its economic value. Additionally, years of selective breeding and habitat fragmentation have raised concerns about declining genetic diversity. Genetic variation is essential for adaptability and resilience in changing environments. Due to these challenges, it is crucial to assess and preserve genetic diversity across yellow catfish populations to inform scientific breeding and sustainable aquaculture.
A study (DOI: 10.48130/animadv-0024-0010) published in Animal Advances on 23 January 2025 by Shiyong Zhang's team, Freshwater Fisheries Research Institute of Jiangsu Province, offers essential guidance for conserving germplasm resources and improving breeding strategies, particularly by incorporating genetically distinct populations into selective breeding programs.
To evaluate the genetic diversity and population structure of yellow catfish, researchers employed ten highly polymorphic microsatellite (SSR) markers across six geographically distinct populations in China. These markers, selected from different chromosomes to avoid linkage disequilibrium, allowed for the amplification of 201 alleles, revealing significant differences in genetic diversity among the populations. The average number of alleles ranged from 9.0 to 11.5 per population, with the Ussuri River population (WSLR) showing the lowest allele count (90) and Hongze Lake (HZHL) the highest (115). Correspondingly, expected heterozygosity (He) ranged from 0.588 to 0.727, and observed heterozygosity (Ho) from 0.614 to 0.667, with WSLR consistently exhibiting the lowest genetic diversity across parameters such as PIC, Shannon's index, and effective allele number. Hardy-Weinberg equilibrium analysis revealed significant deviations at multiple loci across populations, especially at PF448 and PF05. Analysis of molecular variance (AMOVA) indicated that 91% of genetic variation occurred within individuals, while only 3% was attributed to differences between populations. Genetic differentiation indices (Fst) ranged from 0.014 to 0.069, suggesting low to moderate differentiation, with the WSLR population showing the most distinct genetic profile. Clustering analyses—including phylogenetic trees, PCoA, and STRUCTURE analysis—clearly separated the northern WSLR population from the five southern populations. Gene flow analysis supported this structure, with high levels of exchange among southern populations but reduced flow with WSLR. These results highlight the influence of geographic isolation on genetic divergence and suggest that the WSLR population, despite its lower diversity, could serve as a valuable genetic resource for breeding programs aiming to enhance adaptability and resilience in yellow catfish aquaculture.
These findings provide a scientific framework for the conservation of yellow catfish germplasm and the design of targeted breeding strategies. The identification of high-diversity populations such as HZHL supports their use as foundational stocks for genetic improvement. Conversely, the genetic uniqueness of the WSLR population offers an opportunity to broaden the genetic base of farmed stocks by introducing potentially adaptive traits. Integrating these insights into breeding programs could improve growth performance, stress resistance, and overall production efficiency, addressing key bottlenecks in yellow catfish aquaculture. Furthermore, this study reinforces the need to maintain natural genetic variation to support long-term sustainability in aquaculture systems.
