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      Genetic structure of natural populations of Cryptocarya moschata Nees (Lauraceae) from southeastern Brazilian Atlantic rain forest Translated title: Estrutura genética de populações naturais de Cryptocarya moschata Nees (Lauraceae) na Mata Atlântica do sudeste brasileiro

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          Abstract

          This study was accomplished on a more comprehensive basis to evaluate previous questions that were raised from a preliminary article about the genetic structure of Cryptocarya moschata populations. Thus, through the analysis of 40 polymorphic allozyme loci, allele frequencies were estimated from 335 individuals of 11 natural populations of C. moschata from six hydrographic basins of São Paulo state and Serra da Estrela, Rio de Janeiro, Brazil. Estimates of Wright's F statistics were done through the analysis of variance, presenting average values of <img border=0 width=32 height=32 id="_x0000_i1026" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f).jpg" align=absmiddle > or = 0.352, <img border=0 width=32 height=32 id="_x0000_i1027" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle > or = 0.285 and <img border=0 width=32 height=32 id="_x0000_i1028" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f2).jpg" align=absmiddle > or = 0.097. These results indicated that individuals within populations must be panmitic, and that the diversity among populations is fairly high, being superior to what would be expected for groups of plants having a full-sib family structure. From estimates of <img border=0 width=32 height=32 id="_x0000_i1029" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>obtained for populations taken two at a time, the model of isolation by distance was tested; data did not fit the model, showing that <img border=0 width=32 height=32 id="_x0000_i1030" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>did not increase by the respective increasing of the geographic distance. The estimated gene flow of 0.55 migrants per generation corroborated the pronounced populational differentiation, indicating that drift effects should be more important than the selection ones. The effective population sizes found from the sampled populations showed that there was an adequate genetic representativeness of the samples for those with relatively low values of <img border=0 width=32 height=32 id="_x0000_i1031" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f2).jpg" align=absmiddle>. Though, under a metapopulation context, the effective population size was 17.07 individuals, indicating that sampling performed for the species corresponded to 88.44% of the maximum effective size obtained from 11 populations with a <img border=0 width=32 height=32 id="_x0000_i1032" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>of 0.285, equivalent to only 5.09% individuals for the total sampled. Management and conservation strategies aimed at preserving high intrapopulation genetic variation in C. moschata would imply in the maintenance of populations with great number of individuals. Moreover, for the preservation of the species as a whole, the maintenance of many such populations would be mandatorily recommended, which denotes that the conservation of large areas of Atlantic rain forest should be necessary to hold its evolutionary dynamics.

          Translated abstract

          Este estudo foi realizado, de forma mais abrangente, para avaliar questões prévias que foram levantadas a partir de um artigo preliminar sobre a estrutura genética de populações de Cryptocarya moschata. Assim, pela análise de 40 locos alozímicos polimórficos, estimaram-se as freqüências alélicas para 335 indivíduos adultos de 11 populações naturais de Cryptocarya moschata, de seis bacias hidrográficas do estado de São Paulo e da Serra da Estrela, no Rio de Janeiro. Obtiveram-se estimativas das estatísticas F de Wright, estimadas pelo método da análise da variância, que apresentaram valores de <img border=0 width=32 height=32 id="_x0000_i1034" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f).jpg" align=absmiddle > ou = 0,352, <img border=0 width=32 height=32 id="_x0000_i1035" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle > ou = 0,285 e <img border=0 width=32 height=32 id="_x0000_i1036" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f2).jpg" align=absmiddle > ou = 0,097, indicando que os indivíduos dentro das populações devem ser panmíticos, que a diversidade entre as mesmas é bastante alta, superior à esperada para famílias com estruturação de irmãos-completos. Calculando <img border=0 width=32 height=32 id="_x0000_i1037" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>com as populações tomadas duas a duas, testou-se o modelo de isolamento pela distância, sendo que os dados não aderiram ao modelo, mostrando não haver aumento de <img border=0 width=32 height=32 id="_x0000_i1038" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>com o respectivo aumento da distância geográfica. O fluxo gênico estimado em 0,55 indivíduos por geração corrobora a pronunciada diferenciação populacional encontrada, indicando que efeitos de deriva devem ser mais importantes do que os de seleção. Os tamanhos efetivos populacionais estimados a partir das populações amostradas mostraram que houve uma adequada representatividade genética das amostras para aquelas com valores de <img border=0 width=32 height=32 id="_x0000_i1039" src="../../../../../../img/revistas/bn/v4n1/img/a04car(f2).jpg" align=absmiddle>relativamente baixos. Contudo, sob um contexto metapopulacional, o tamanho efetivo populacional foi de 17,07 indivíduos, indicando que a amostragem realizada para a espécie correspondeu a 88,44% do tamanho efetivo máximo obtido a partir de 11 populações com um <img border=0 width=32 height=32 id="_x0000_i1040" src="../../../../../../img/revistas/bn/v4n1/img/a04car(0p).jpg" align=absmiddle>de 0,285, correspondendo a apenas 5,09% dos indivíduos amostrados. As estratégias de manejo e conservação necessárias para a preservação da alta variabilidade genética intrapopulacional de C. moschata implicam na manutenção de populações com número grande de indivíduos. Além disso, para a preservação da espécie como um todo, a manutenção de muitas populações se faz necessária, o que denota que a conservação de grandes áreas de Mata Atlântica deva ser necessária para manter sua dinâmica evolutiva.

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          Most cited references53

          • Record: found
          • Abstract: found
          • Article: not found

          Estimation of average heterozygosity and genetic distance from a small number of individuals.

          M Nei (1978)
          The magnitudes of the systematic biases involved in sample heterozygosity and sample genetic distances are evaluated, and formulae for obtaining unbiased estimates of average heterozygosity and genetic distance are developed. It is also shown that the number of individuals to be used for estimating average heterozygosity can be very small if a large number of loci are studied and the average heterozygosity is low. The number of individuals to be used for estimating genetic distance can also be very small if the genetic distance is large and the average heterozygosity of the two species compared is low.
            Bookmark
            • Record: found
            • Abstract: not found
            • Article: not found

            The detection of disease clustering and a generalized regression approach.

            N Mantel (1967)
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              The genetical structure of populations.

              S. Wright (1951)
                Bookmark

                Author and article information

                Journal
                bn
                Biota Neotropica
                Biota Neotrop.
                Instituto Virtual da Biodiversidade | BIOTA - FAPESP (Campinas, SP, Brazil )
                1676-0611
                2004
                : 4
                : 1
                : 01-16
                Affiliations
                [02] Piracicaba SP orgnameUSP orgdiv1CENA orgdiv2Laboratório de Melhoramento de Plantas Brazil
                [01] Campinas SP orgnameUNICAMP orgdiv1Departamento de Botânica Brazil
                Article
                S1676-06032004000100004 S1676-0603(04)00400100004
                ca2e0659-f50a-46da-ba47-8d16418984f1

                This work is licensed under a Creative Commons Attribution 4.0 International License.

                History
                : 17 March 2003
                : 18 January 2004
                : 12 February 2004
                Page count
                Figures: 0, Tables: 0, Equations: 0, References: 56, Pages: 16
                Product

                SciELO Brazil

                Self URI: Full text available only in PDF format (EN)
                Categories
                Articles

                Brazil,estrutura genética,Lauraceae,alozimas,Neotrópico,Cryptocarya moschata,Mata Atlântica,Brasil,Atlantic rain forest,Neotropics,genetic structure,allozymes

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