Genetic diversity and struture of Bertholletia excelsa, an Amazonian species of wide distribution

Author(s)

Patrícia Sanae Sujii

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2011-02-03

Examining board members

Vera Nisaka Solferini; Evandro Marsola de Moraes; Alexandre Siqueira Guedes Coelho

• Advisor: Vera Nisaka Solferini; Vânia Cristina Rennó Azevedo

Abstract

Amazonian upland forests are wide formations and can compose large continuous forests. There are several studies about population genetic structure of species in this kind of forest, but there are few studies that aim to understand the genetic structure along the Amazon. Brazil-nut tree is a monotypic species, Bertholletia excelsa, endemic to upland forests and distributed along almost the entire expanse of the Amazon. This study aimed to evaluate genetic structure of Bertholletia excelsa populations over Amazon and verify if the structuring is influenced by distance between them. Material from 379 individuals was collected in nine subpopulations distributed in five states. Seven microsatellites markers were developed to the species and were used with four others, previously published, to samples genotyping. Analyses within and among populations were performed to evaluate genetic diversity and population structure. Genetic distance estimates were correlated to different potential factors to find possible causes to genetic structure. A few alleles were found in each subpopulation and considerable variation was observed in alleles found in each subpopulation and in their allele frequencies, especially when compared very distant subpopulations. Heterozygote excess was observed in five subpopulations while in the other four subpopulations non-significantly different from zero estimates of FIS were found. Fine-scale structure, when present, was small. Estimates to inter population genetic structure varied from low ('teta' = 0,02) to higt ('teta' = 0,244) values. B. excelsa genetic structure can be analysed considering three different scales: (i) within population; (ii) among moderately distant populations (<500km); and among very distant subpopulations. At all scales, significant correlations were found between genetic structure and geographic distance between pairs of individuals or populations. It may indicate that distance is an important factor to this population's genetic structure, but probably there are other factors acting together, especially at great geographical scales (AU)

• FAPESP's process: 09/03485-0 - Genetic Diversity and structure of Bertholletia excelsa in fragmented areas
• Grantee: Patricia Sanae Sujii
• Support Opportunities: Scholarships in Brazil - Master