Allozyme electrophoresis was used to investigate genetic population structure among 245 individuals of the silverside Odontesthes argentinensis sampled from localities in southern Brazil and Uruguay. Striking differences in allozyme frequencies and genetic variability were detected among localities. Analysis of these differences indicated two distinct populations: one distributed in a wide marine coastal zone; and one in the peripheral environment of the Patos Lagoon estuary in southern Brazil. The population in Patos Lagoon appears to have originated from an ancestral marine population and been established in the estuary by a founder effect. The extent and pattern of genetic divergence found in our study, the existence of diverse reproductive strategies in the estuarine silversides, and differences in morphology of eggs and larvae, indicate that speciation is taking place in Patos Lagoon. It is suggested that the two populations should be considered separately when formulating management and conservation strategies.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 2000 • No. 2