Genome size estimates for two important freshwater molluscs, the zebra mussel (Dreissena polymorpha) and the schistosomiasis vector snail (Biomphalaria glabrata).

The haploid genome sizes of two important molluscs were assessed by Feulgen image analysis densitometry. The genome size of the zebra mussel (Dreissena polymorpha), a prolific invader of North American lakes, was estimated to be 1C = 1.70 +/- 0.03 pg, and that of the freshwater snail Biomphalaria glabrata, the predominant intermediate vector of the human parasite Schistosoma mansoni, was estimated at 0.95 +/- 0.01 pg. These estimates will be important in future efforts in molluscan genomics, which at present lags far behind work being carried out with vertebrate and arthropod models. B. glabrata in particular, which has one of the smallest known gastropod genomes, is recommended as a highly suitable target for future genome sequencing.