NATURAL HYBRIDIZATION IN FRESH-WATER ANIMALS - ECOLOGICAL IMPLICATIONS AND MOLECULAR APPROACHES

The number of cases where the phenomena of hybridization and gene intr ogression have been found in species interactions is steadily increasi ng, in both plant and animal taxa. During the last few years, many exa mples have been detected even in otherwise well-known freshwater anima l taxa. We discuss the topic with respect to ecology and evolutionary processes and compare the main potentials and limitations of allozymes , mitochondrial DNA, and RAPD markers to address some important geneti c issues of interspecific hybridization in natural populations of sele cted freshwater model systems.