Genetic diversity and clonality of the Asian clam Corbicula fluminea are reflected by inner shell color pattern.
The Asian clam Corbicula fluminea is self-compatible, hermaphroditic, androgenetic, and ovoviviparous. Androgenesis is a type of asexual male reproduction; although it involves genetic recombination, the offspring retain the same genome as their male parent. Despite this unique reproductive character of C. fluminea, considerable morphological diversity and internal shell color were observed among specimens collected from six locations in Taiwan. We investigated these specimens through morphological examination and amplified fragment length polymorphism (AFLP). Twenty-three AFLP genotypes were found in 48 individuals by using only one primer combination. AFLP was applied for identifying the clonal lineage of C. fluminea successfully. Our results showed that among specimens with different genotypes, external shell color could be affected by environmental factors, such as substrate, showing the same pattern, but internal shell color was determined purely by genetics. This relationship between the inner shell color variation and genotype in C. fluminea can be easily used to study the dispersal of this invasive species and in breeding for aquaculture.