Analysis of Genetic Diversity and Population Structure Among Different Geographical Populations of Babylonia areolata

The ivory shell, Babylonia areolata, is an economically important gastropod along the southeastern coast of China and throughout Southeast Asia. In recent years, overfishing and habitat degradation have driven a continuous decline in wild stocks, while large-scale hatchery propagation and cross-regional translocation pose potential threats to the genetic integrity of germplasm resources. To assess the current genetic diversity and population structure of different geographical populations, 14 microsatellite markers were used to analyse four wild populations collected from Hainan (HH), Zhanjiang in Guangdong (ZJ), Zhao’an in Fujian (ZA), and Changle in Fujian (CL), together with one selectively bred population introduced from Thailand (TT). All five populations maintained high genetic diversity, and the selectively bred TT showed the lowest allelic richness. Pairwise Fst ranged from 0.003 to 0.076: the selectively bred TT population was moderately differentiated from the three mainland populations (Fst = 0.073–0.076) but only weakly differentiated from HH (0.038). AMOVA showed that most genetic variation resided within individuals, with only 4.31% among populations. PCoA, STRUCTURE and UPGMA analyses consistently resolved two major lineages: CL, ZA and ZJ formed one clade, whereas HH and TT clustered together in a second clade. Overall, wild B. areolata populations still retain high genetic diversity with generally weak differentiation among populations, whereas the introduced selectively bred population already shows reduced allelic richness. These findings provide a scientific basis for wild germplasm conservation, translocation management, and genetic breeding of B. areolata.