The knowledge and understanding about the spatial genetic structure are important for management and conservation of forest resources, as well as to evaluate the impacts of exploitation and fragmentation and establish the strategies of sampling in natural populations. We analyzed the spatial genetic structure (SGS) in natural populations of Dimorphandra mollis Benth. to gather information about in situ genetic conservation. A total of ten allozyme polymorphic loci were used to estimate the frequency of 20 alleles in 180 individuals in three natural populations (Vargem da Cruz, Campina Verde and Pau de Fruta) in the north of Minas Gerais State, Brazil. The results revealed high genetic diversity in these populations, showing an average number of alleles per locus (Â) of 2.0. All loci were polymorphic and the average genetic diversity (Ĥe) was 0.463. The genotypes of D. mollis in Vargem Grande and Pau de Fruta populations exhibit weak SGS with a close-to-random spatial distribution of genotypes (b log = -0.007, P = 0.171; b log = -0.004, P = 0.772, respectively). On the other hand, the genotypes of the Campina Verde population exhibit positive spatial autocorrelation indicating that groups of individuals are highly related (F(300,m) = 0.05, P < 0.001). The SGS was confirmed by Sp statistics (Sp = 0.047, P < 0.001). This could be due to restricted pollen and seed dispersal and the anthropic pertubation history of this area; these factors are likely to contribute to the familiar structure observed among these genotypes. The genetic structure in these populations needs to be taken into account when sampling from these sites to ensure that in situ conservation strategies will be more effective.
allozymes; Cerrado; coancestry; genetic conservation; tree species
