GENETIC-DIVERGENCE AND PHYLOGENETIC-RELATIONSHIPS AMONG SALMO-TRUTTA L (BROWN TROUT) POPULATIONS FROM GREECE AND OTHER EUROPEAN COUNTRIES

In order to clarify the genetic structure and the phylogenetic relatio nships among brown trout (Salmo trutta) populations from Greece and ot her European countries starch gel electrophoresis was used. The popula tions come from various rivers from Greece and other European countrie s, flowing to the Atlantic or to the Mediterranean. Eleven enzymic sys tems were investigated. These correspond to 26 putative loci. A high d egree of genetic polymorphism was found. The percentage of polymorphic loci ranged from 3.8 to 34.6 and the degree of expected heterozygosit y from 0.016 to 0.1. F-statistics and clustering analyses indicated th e existence of a high degree of differentiation. This differentiation is mainly between the Atlantic and the Mediterranean populations. Furt hermore the Mediterranean populations seem to be divided into two grou ps. One includes the western Mediterranean populations and populations from western Greece and the other north-eastern Greek populations. Th e latter seem to be related to other Balkan populations and probably t o Danubian or Black Sea populations. These results support the idea of two different lineages of Mediterranean brown trout populations, one of which is probably of aboriginal origin.