Genetic characteristics of hybrid populations derived by crossing Chinese and Indian pearl oysters, Pinctada fucata, based on AFLP markers

Abstract

In selective breeding, hybrid populations of pearl oysters Pinctada fucata were made by crossing Indian pearl
oysters with Chinese ones. Genetic characteristics of 2 hybrid populations, Indian( ) × Sanya( ) and Sanya( ) ×
Indian( ) and 2 pure populations, Indian × Indian and Sanya × Sanya, were investigated using AFLP markers. A total
of 230 loci were generated by 3 pairs of primer combinations. Indian-Sanya hybrid showed the highest proportion of
polymorphic loci (99.6%) and the largest number of dominant, monomorphic loci (38). Gene diversity was 0.422 for
total, 0.364 for average, ranging from 0.360 to 0.372. The level of gene diversity in Indian-Sanya (0.372) was
significantly higher than those in the other populations (P < 0.001). Significant and high levels of overall and
pairwise genetic differentiation were observed among the 4 populations as revealed by GST and AMOVA. These
results suggested that both the hybrid and pure populations were characterized by high levels of genetic diversity
and genetic differentiation at the beginning of selection, implying that artificial reproduction could have more impact
on genetic differentiation than on genetic diversity at the first stage of selective breeding. Yet the high level of
genetic divergence among populations suggested that monitoring changes of genetic variation of selected strains is
necessary and critical for rational management of brood stocks in selective breeding practice.