GENETIC DIVERSITY AND MANAGEMENT OF BROWN TROUT - THE VALUE OF STUDYING VARIATION AT PROTEIN AND MICROSATELLITE LOCI

Genetic diversity and management of brown trout: the value of studying variation at protein and microsatellite loci. The electrophoretic pol ymorphism at 47 protein loci was studied in 24 domesticated and natura l French brown trout populations. The variation at 5 microsatellite lo ci in 4 of these populations was also investigated. The total proporti on of polymorphic loci was 57% for all the populations analysed and ra nged from 0 to 37% between populations. This polymorphism allowed us t o distinguish 2 subspecies which occupy the Atlantic and Mediterranean areas, respectively. The average standard genetic distance between th ese 2 groups was estimated to be 0.10. The genetic diversity of the At lantic populations was substantially higher than that of the Mediterra nean populations and showed some geographic structuration. All the dom esticated stocks originated from the Atlantic area. The 5 microsatelli te loci were polymorphic with a total number of alleles per locus rang ing from 2 to 8 and heterozygosity was between 0 and 74%. These micros atellite loci also allowed us to distinguish the Mediterranean populat ion from the 3 populations originating from the Atlantic area. The val ue of these results for the genetic management of brown trout is brief ly discussed.