Helena A V Souza

Federal University of Minas Gerais, Cidade de Minas, Minas Gerais, Brazil

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Publications (4)6.17 Total impact

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    ABSTRACT: • Premise of the study: Microsatellite loci were isolated and characterized for use in population genetic studies of Plathymenia reticulata (Fabaceae), a tropical tree widespread in the Atlantic Forest and cerrado biomes of South America. • Methods and Results: Nine microsatellite markers were developed using a simple sequence repeat-enriched library. Polymorphism was analyzed in 51 individuals from two populations. All loci were polymorphic, with the number of alleles per loci ranging from five to 15 (mean number of alleles: 10.22). Observed and expected heterozygosities per loci and population ranged from 0.313 to 1.000 and 0.280 to 0.869, respectively. • Conclusions: These highly informative loci are potentially useful to estimate population genetic structure and to understand evolutionary processes and taxonomy of the species.
    American Journal of Botany 04/2012; 99(5):e210-2. · 2.59 Impact Factor
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    ABSTRACT: • Premise of the study: Microsatellite markers were developed for Dimorphandra mollis (Leguminosae), a widespread tree in the Brazilian cerrado (a savanna-like vegetation). • Methods and Results: Microsatellite markers were developed from an enriched library. The analyses of polymorphism were based on 56 individuals from three populations. Nine microsatellite loci were polymorphic, with the number of alleles per locus ranging from three to 10 across populations. The observed and expected heterozygosities per locus and population ranged from 0.062 to 0.850 and from 0.062 to 0.832, respectively. • Conclusions: These microsatellites provide an efficient tool for population genetics studies and will be used to assess the genetic diversity and spatial genetic structure of D. mollis.
    American Journal of Botany 03/2012; 99(3):e102-4. · 2.59 Impact Factor
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    ABSTRACT: Dimorphandra mollis (Leguminosae), known as faveiro and fava d'anta, is a tree that is widely distributed throughout the Brazilian Cerrado (a savanna-like biome). This species is economically valuable and has been extensively exploited because its fruits contain the flavonoid rutin, which is used to produce medications for human circulatory diseases. Knowledge about its genetic diversity is needed to guide decisions about the conservation and rational use of this species in order to maintain its diversity. DNA extraction is an essential step for obtaining good results in a molecular analysis. However, DNA isolation from plants is usually compromised by excessive contamination by secondary metabolites. DNA extraction of D. mollis, mainly from mature leaves, results in a highly viscous mass that is difficult to handle and use in techniques that require pure DNA. We tested four protocols for plant DNA extraction that can be used to minimize problems such as contamination by polysaccharides, which is more pronounced in material from mature leaves. The protocol that produced the best DNA quality initially utilizes a sorbitol buffer to remove mucilaginous polysaccharides. The macerated leaf material is washed with this buffer until there is no visible mucilage in the sample. This protocol is adequate for DNA extraction both from young and mature leaves, and could be useful not only for D. mollis but also for other species that have high levels of polysaccharide contamination during the extraction process.
    Genetics and molecular research: GMR 01/2012; 11(1):756-64. · 0.99 Impact Factor
  • Helena A. Viana e Souza, Maria Bernadete Lovato
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    ABSTRACT: We performed a comparative analysis of the genetic diversity and structure of two congeneric tree species, one critically endangered, with only 21 known individuals in the wild, Dimorphandra wilsonii, and the other widely distributed Dimorphandra mollis. Eight populations of D. mollis and all known trees of D. wilsonii, from three areas, were screened for variability with ISSR markers. Percentage of polymorphic bands, Nei's gene diversity and Shannon's index were considerably lower in D. wilsonii (P = 40.0%, h = 0.124 and I = 0.190), as compared to D. mollis (P = 70.4%, h = 0.190 and I = 0.297). Bayesian clustering showed that D. wilsonii individuals are clustered in three populations, which had high differentiation among them. Several measures for their conservation were suggested: protection of all extant populations, ex situ conservation of seeds, production of saplings in nurseries and foundation of new populations in reserve areas.
    Biochemical Systematics and Ecology - BIOCHEM SYST ECOL. 01/2010; 38(1):49-56.