Estrutura genética e sistema de cruzamento em Eugenia dysenterica DC. (Mvrtaceae)

• Autor(a) principal: Barbosa, Ana Clara de Oliveira Ferraz
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/3881
• topic: Cagaiteira; Diversidade; Estrutura genética; Microssatélites; Sistema misto; Cagaiteira; Diversity; Genetic structure; Microsatellites; Mixed system; GENETICA::GENETICA VEGETAL

The genetic structure of a species corresponds to the amount of genetic variability and its distribution within and among local populations and individuals. The patterns of variability among individuals in a local population are highly dependent of mating system. The goal of this study was to evaluate the mating system, the diversity and genetic structure in populations of E. dysenterica in local and regional scale. The assessment of the mating system and the analysis of genetic structure at the local scale were performed in a population of Mimoso – GO and for the analysis of genetic structure at the regional scale were analyzed 23 natural populations of E. dysenterica derived from six Brazilian states (Goiás, Minas Gerais, Bahia, Mato Grosso, Tocantins and Piauí). For all studies seven polymorphic microsatellite loci were used. Considering the 20 families analyzed, the multilocus outcrossing rates (tm = 0.918) and single locus (ts = 0.797) were high and significant. From a total of 399 seeds evaluated, it was possible to determine the pollen donor to 218 seeds (55%) with confidence level of 90%, 174 seeds (44%) with confidence level of 95% and 65 seeds (16%) with confidence level of 99%. In 15 families evaluated were possible to verify the occurrence of multiple paternity, with the number of pollen donor per fruit ranged from one to three. The results presented show that the species E. dysenterica presents mixed mating system and that there is multiple paternity in this species. The intrapopulational spatial genetic structure was positive (R2 = 0.01646, p < 0.001), which was expected since species generally have spatial restriction to disperse. The spatial genetic structure was significant (Sp = 0.0143) and genetic neighborhood (Nb) was equal to 69.93 km. On average, about 30 individuals were analyzed by subpopulation for all loci. The average number of alleles per locus was equal to 9, the genetic diversity was high (0.725) and the observed frequency of heterozygotes (Ho) was 0.610. Were found 18 private alleles in 10 subpopulations. The results for the fixation index ((f) in the subpopulations ranged between -0.058 and 0.338, with an overall value of 0.162, indicating excess of homozygotes in relation to the expected under HWE. The genetic differentiation between subpopulations can be considered relatively high (FST = 0.161). The Mantel test indicates that the genetic divergence of 24 subpopulations evaluated is structured in geographic space (r = 0.427, p < 0.001), suggesting that the model of isolation by distance or stepping-stone are adequate to explain the spatial pattern of genetic divergence among subpopulations of E. dysenterica evaluated.