Genetic diversity of populations of the freshwater shrimp Macrobrachium borellii (Caridea: Palaemonidae) evaluated by RAPD analysis

We evaluated the genetic diversity of 2 populations of the pampean fresh-water shrimp Macrobrachium borellii at its most southern geographical distribution by means of the PCR-based technique RAPD (random amplified polymorphic DNA). As a result of either small population size, greater degree of isolation, or greater inbreeding, genetic diversity was lower in an artificial pond population than in a population from a small tributary of the Rio de la Plata. The high level of diversity scored in this species with RAPD markers is striking in comparison to the low H values reported by other authors for decapods, including Macrobrachium rosenbergii, with allozyme markers. These results demostrate that RAPD polymorphisms can be useful measures of diversity in these taxa.