Estudo de estrutura genética da espécie de Cactácea colunar Pilosocereus machrisii utilizando DNA microssatélite

• Ano de defesa: 2012
• Autor(a) principal: Perez, Manolo Fernandez
• Orientador(a): Moraes, Evandro Marsola de
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Carlos
• Programa de Pós-Graduação: Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular - PPGGEv
• País: BR
• Palavras-chave em Português: Pilosocereus machrisii; Estrutura populacional; Campos rupestres; Microsatélites; Distribuição fragmentada; Genética e evolução
• Palavras-chave em Inglês: Pilosocereus machrisii; Population structure; Campos rupestres; Microsatellites; Patchy distribution
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::GENETICA
• Link de acesso: https://repositorio.ufscar.br/handle/20.500.14289/5504

Pilosocereus machrisii is a columnar cacti with natural fragmented distribution; restrict to campos rupestres vegetation patches or rocky outcrops on the Cerrado domain; in Central and eastern Brazil. These features makes P. machrisii an appropriate biological model for population genetic studies aiming to gather information on population structure; since small and isolated populations are often vulnerable to genetic drift and high levels of inbreeding. Genetic diversity and population structure were assessed for ten microsatellite loci in 12 P. machrisii populations; covering the majority of the species distribution. Genetic diversity levels were relatively similar on sampled populations; except for Brotas-SP samples; that showed lower levels than those observed for other locations. Significant Hardy Weinberg Equilibrium departures were detected in eight different populations; for one or two loci. High levels of genetic differentiation and private alleles with elevated frequencies were detected; with total FST value of 0.357. The genetic structure of P. machrisii was analyzed with STRUCTURE and SAMOVA softwares; and populations were grouped in four main clusters; with secondary structure on two of these clusters. Significative levels of correlation between genetic and geographic distances were observed for the whole dataset; however; when the genetic groups were analyzed separately; no correlation was verified. Furthermore; the genetic relationship between the populations was observed with a principal coordinate analysis (PCA) and an UPGMA dendrogram. The genetic structure observed in P. machrisii suggests that historical factors caused populations fragmentation; with subsequent geographic isolation and high genetic differentiation between them.