Low genetic diversity in broodstocks of endangered Chinese sucker, Myxocyprinusasiaticus: implications for artificial propagation and conservation

Abstract. The releasing program of Chinese sucker (Myxocyprinusasiaticus) has been conducted for years in China. To prevent loss of genetic variation in wild populations, it is important to assess and monitor genetic diversity of broodstocks before release of offspring. Three broodstocks (Pixian Base of Sichuan Fisheries Research Institute, China (PBS), Yibin Base of Sichuan Fisheries Research Institute, China (YBS) and Yibin Rare Aquatic Animal Research Institute, China (YRA)) were investigated using mitochondrial control region and 12 microsatellites. The relatively low genetic diversities of these broodstocks were detected (PBS, haplotype diversity (h) = 0.877, observed heterozygosity (Ho) = 0.416; YBS, h = 0.812, Ho = 0.392; YRA, h = 0.818, Ho = 0.365). PBS showed higher Ho than YBS and YRA (P < 0.05). Genetic divergence (F(ST)) based on microsatellites between PBS and YRA was significant (F(ST) = 0.1270, P < 0.05), the same situation happened between YBS and YRA (F(ST) = 0.1319, P < 0.05). However, divergence between PBS and YBS was not significant (F(ST) = 0.0029, P > 0.05). Structure analysis revealed that YRA were distinct from PBS and YBS. Based on these results, it is important to propose some suggestions of genetic management for artificial propagation of Chinese sucker, such as broodstock exchange among hatcheries and broodstock supplement from wild.