A noninvasive method for extracting bivalve DNA from the water-filled mantle cavity

Genetic studies play a great role for determining the biology of bivalves, particularly those covering population genetics, phylogeny, breeding, stock management, and conservation. However, DNA sampling methods that require removal of bivalves from the water and/or opening of their shells often cause stress and damage to bivalves, which can be lethal. The invasiveness of DNA sampling has made it difficult to conduct genetic studies in threatened species, rare species, and/or breeding lineages. In the present study, we developed a non-invasive method for bivalve DNA sampling using the water-filled mantle cavity (WMC). Our method can extract DNA from a small WMC sample (about 100 mu l), collected using a fine needle and syringe without opening the shell. We demonstrated that the WMC sample contains intact mitochondrial and nuclear DNA. DNA contamination from other organisms, such as adjacent bivalve individuals, did not affect the resulting PCR and DNA sequencing analyses. Finally, the individuals from whom WMC was collected remained alive for more than 2months after the experiments. This non-invasive method will be of great assistance in investigating the genetics of bivalves.