Estudo de genética populacional no Pato-Mergulhão, Mergus octosetaceus

• Ano de defesa: 2012
• Autor(a) principal: Luciana de Rezende Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Genética
• Link de acesso: http://hdl.handle.net/1843/BUBD-933K5T

Several populations of endangered species are being decimated by man worldwide. Several species had their populations rapidly decreased in the last century, some to the point of extinction. Genetic diversity is necessary for the species to keep their reproductive success, their resistance to disease and ability to adapt to environmental changes. The microsatellite markers have been widely used in studies of population genetics because they are highly variable and are also important tools for studying threatened species. The Brazilian Merganser is one of the rarest birds of the Americas, classified as critically endangered in the List of Endangered Species of Brazilian Fauna and in the World Red List. The aim of this study was to evaluate the genetic diversity of the main remaining populations (Serra da Canastra National Park, Chapada dos Veadeiros National Park and Serra do Salitre) of the Brazilian Merganser and to analyze the kinship among individuals. To achieve these goals we used six microsatellite loci in 82 samples. We found low genetic variability in Brazilian Merganser, when compared with other species from the Anatidae family. The population of the Serra da Canastra showed deviation from Hardy-Weinberg equilibrium for all loci, and a signal of recent bottleneck. Despite the low genetic diversity, remnant populations of the Brazilian Merganser present significant differentiation between Serra do Salitre and Chapada dos Veadeiros, and between Serra da Canastra and Serra do Salitre. The kinship analysis showed that 35% of the individuals were related, 22.5% of them highly related (parents-children, siblings, uncles- nephew, grandparents-grandson) and 12.5% slightly related (cousins). The high relatedness degree between sampled individuals from all locations is expected for a species with a very small population size. Thus we conclude that the population of Brazilian Merganser suffered a recent bottleneck and subsequent loss of genetic diversity. This population suffers from the effects of inbreeding and genetic drift, which increases the loss of the genetic variability of the species. However, the remaining populations showed some degree of genetic structuration, suggesting a relative independence of some demographic units. The preservation of these units is extremely important o maintain the genetic variation of the species, thus preventing their extinction.