Hybrid origin of polyploidy in freshwater snails of the genus Bulinus ( Mollusca: Planorbidae).

G-banded karyotypes of the diploid freshwater snail, Bulinus tropicus, and of the tetraploid, B. truncatus, were studied in order to determine whether the tetraploid had arisen through hybridization of karyotypically distinct taxa or through simple doubling of the genome, and to infer cytological characteristics of the diploid taxa involved in the origin of the tetraploid.-from Authors