ALLOZYME VARIABILITY IN BROWN TROUT SALMO-TRUTTA IN CHILE

1. Brown trout ova were imported during the last century from differen t locations in Europe to establish populations in Chilean rivers (Sout h America). The rivers are currently occupied by naturalized populatio ns that have adapted to very different environmental conditions, such as areas of semi-desert in the north, or rainy and cold areas in the s outh. 2. In this first study in this geographical area, electrophoreti c variability of proteins encoded by twenty-five loci was screened in seven populations from northern to southern Chile. 3. The results show significant heterogeneity of allelic frequencies between populations in seven of eleven polymorphic loci detected. The estimated value of g enetic diversity 0.1274 (H-T) is higher than that observed in populati ons from areas of natural distribution of this species. However, only 12.64% of this genetic diversity was found between samples (G(ST)), in dicating a low genetic divergence among Chilean populations. The obser ved associations among the Chilean and 'modern' group of European popu lations suggests the probable origin of the new populations.