Evolution de la variabilité génétique inter et intra-populations de populations de Salmonidés issues de mêmes pools géniques

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Abstract
Through electrophoretic analysis of 14 enzymatic systems corresponding to 31 loci, we studied the change over six generations in the intra- and inter-population variability of salmonid populations from the same initial genetic pool. Four collections of brook trout (Salvelinus fontinalis) and five of brown trout (Salmo trutta) from recently acclimatized stocks in the Kerguelen Islands were examined. The heterozygosity level of these populations remained high and corresponded to the levels of variability observed in other polymorphism studies of the same species. In each species, there was a consistent pattern of genetic differentiation with the "hydrographic proximity" of the populations and with the genetic origin. Within one and the same initial genetic pool, the dendrograms grouped primarily the different ecotypes collected in the same hydrographic system. Thus, these ecotypes seem to result from a behavioral variability within a panmictic population. Finally, establishment of time–genetic distance relationships on the sole basis of electrophoretic data appears unwarranted.