GENETIC STRUCTURE OF POPULATIONS OF ARBOREAL SPECIES NATIVE TO SERPENTINE SOILS OF THE CERRADO

Abstract

This research was carried out to evaluate the effects of the adaptation to serpentine soils on the genetic structure of plant populations from the Cerrado region of Central Brazil, and establish a DNA extraction protocol for the studied species. Four populations of two species, Hymenaea stignocarpa (jatobá) and Bowdichia virgiloides (sucupira-preta), were studied. Two were collected on serpentine soils and the other two on heavy metal free soils. RAPD molecular marker data from collected individuals were used to evaluate the level of variability and the level of genetic divergence between populations of the same species. The genetic structure was studied using the AMOVA procedure via estimation of the components of genetic variance associated with regions (serpentine vs. non-serpentine). The results were not statistically significant, although some level of divergence between regions had been suggested by a UPGMA dendrogram based on the Jaccard similarity index. The estimate of genetic diversity between populations within group () was statistically significant for ";sucupira-preta"; (0.1189) and ";jatobá"; (0.0692). These results suggest that strong selection pressures derived from the presence of toxic elements in serpentine soils did not promote the reproductive isolation necessary to allow the development of a detectable genetic divergence among populations from serpentine and non serpentine soils.

KEY-WORDS: Serpentine soils; genetic drift; RAPD.