Diferenciação genética e diversidade em populações naturais de Cryptocarya aschersoniana Mez (Lauraceae)

Abstract

The genetic variability and structure of natural populations of Cryptocarya aschersoniana Mez were investigated by means of isozymes. Leaf samples of 267 adult individuals were collected from 12 populations native of "Floresta de Planalto" of the State of São Paulo and Southern Minas Gerais State, Brazil. From 39 polymorphic allozyme loci analysed, the divergence obtained through G ST estimates suggests the existence of significant genetic drift and/or natural selectioneffects between populations. The level of gene differentiation ( ĜST = 0.340) was extremely high. The within sample gene diversity (H S = 0.365) account for 66.12% of the overall gene diversity, indicating a greater variability occurring within populations than among them. Goodness of fit tests for mutation-drift equilibrium showed that none of these populations was in equilibrium. From coancestry distance of Reynolds, divergences between pair of populations were also relatively high, which could be associated to bottleneck effects due to present forest fragmentation in analysed populations.