Filolegrafia e fluxo gênico em espécies do gênero Caryocar

• Ano de defesa: 2012
• Autor(a) principal: SOUZA NETO, Advaldo Carlos de
• Orientador(a): COLLEVATTI, Rosane Garcia
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Ecologia e Evolução
• Departamento: Ciências Biológicas - Biologia
• País: BR
• Palavras-chave em Português: Estrutura genética; quaternário; refúgios; coalêsncia
• Palavras-chave em Inglês: Genetic structure; quaternary; refuges theory; coalescence
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::ECOLOGIA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/2573

The genus Caryocar is formed by tree species and is distributed in the neotropical region. Many species of the genus are found in forested biomes, but three species are found in the dry diagonal that cuts the two Brazilian biomes of tropical forests: C. brasiliense, C. coriaceum and C. cuneatum. Understand the phylogeographic pattern of these species may help to comprehend the historic events responsible for the actual biogeographic patterns of the region. In this context, the aim of our study was evaluate the genetic variability of the species that are found in the Brazilian dry diagonal, observe how it s distributed in the sampled populations and, from the data, try to construct a phylogeographic hypothesis for the origin of these species. We sequenced two chloroplastic regions, trnH-psbA and trnC-ycf6, from nine species of the genus Caryocar, for a better understanding of the dry diagonal group origin relative to the species that are found in the tropical forests biomes. We inferred the genetic diversity indices; the relationship between the species, using a network and a Bayesian phylogenetic tree; and we inferred the Time to the Most Recent Common Ancestor of the groups of interest using coalescence based methods. We analyzed 785 base pairs and found 23 haplotypes, some of them are shared between species, demonstrating the possibility of incomplete lineage sorting or hybridization between species of the genus. The species presented low genetic diversity indices, and we found genetic structure in the Caryocar brasiliense populations. The populations from the northern and western threshold of the C. brasiliense distribution presented evidences that they may have functioned as a source of migrants to the other populations. The date of the divergence time reveals that the dry diagonal group has originated around 2,48 millions years before present, and the ancestor of the C. coriaceum e C. cuneatum appeared around 1,21 million years before present, at the beginning of the glacial periods, at Pleistocene. It suggests that these glacial periods had influenced the actual distribution of the species.