Diversidade e estrutura genética espacial de Annona crassiflora MART. (Annonaceae) em área conservada e antropizada do Cerrado

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2011-06-21

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Universidade Federal de Goiás

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The spatial genetic structure is the non-random distribution of genotypes within a population as the outcome of gene flow, genetic drift and selection. Annona crassiflora (Annonaceae) is a hermaphroditic tree. Pollination is entomophilous, being carried by beetles of the genus Cyclocephala (Scarabeidae). Seed dispersal is zoochorous mainly done by Tapirus terrestris. This study aimed to compare the genetic diversity and spatial genetic structure in two populations of Annona crassiflora, one in a conserved area and other in a disturbed area. We analyzed 97 plants from a population at the Ecological Station of Águas Emendadas (ESECAE) in the Federal District (conserved area) and 87 plants in Padre Bernardo (PBE), Goiás (disturbed area), based on eight microsatellite loci developed for the species. PCR products were electrophoresed in ABI3100 automatic DNA sequencer to obtain the genotypes. For a total of eight loci, the number of alleles ranged from 6 to 23 with an average of 15,75 alleles per locus.The allelic richness per population was larger in ESECAE population than PBE population. Expected and observed heterozygosity values were 0,614±0,145 and 0,499±0,181, significant f values were found for PBE, showing nonrandom mating. In ESECAE population expected and observed heterozygosity values were 0,746±0,134 and 0,723±0,173 and f value were not significant, suggesting random mating, the allele frequencies are following the expected ratios for the Hardy-Weinberg equilibrium (p<0,003). Analysis of spatial genetic structure in ESECAE population, showed little absence of autocorrelation (b=-0,00478; p<0,05 R2 = 0,001, p = 0,0257). In PBE population, autocorrelation analysis showed that kinship is slightly related to the logarithm of distance, showing a gene flow pattern like isolation by distance (b=-0,01958; p<0,05 R² = 0.001, p <0,0001). The significant value of θ (0,239) showed that populations are highly differentiated. Also, under the bottleneck test, a population does not showed up in mutation-drift equilibrium, reveling events of recent bottleneck effects. The study suggests that the species may be highly affected by fragmentation and disturbance of their natural habitats augmenting inbreeding, and leading to high genetic differentiation among populations and significant spatial structure, that may be the outcome of restriction to gene flow.

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GOUVEIA, Felipe Oliveira. Diversity and spatial genetic structure of Annona crassiflora MART. (Annonaceae) in conservation and disturbed Cerrado area.. 2011. 59 f. Dissertação (Mestrado em Ciências Biológicas - Biologia) - Universidade Federal de Goiás, Goiânia, 2011.