Diversidade entre e dentro de populações simuladas sob deriva genética

• Ano de defesa: 2008
• Autor(a) principal: Sánchez, Carlos Felipe Barrera
• Orientador(a): Cruz, Cosme Damião
• Banca de defesa: Cecon, Paulo Roberto , Ferreira, Adésio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Genética e Melhoramento
• Departamento: Genética animal; Genética molecular e de microrganismos; Genética quantitativa; Genética vegetal; Me
• País: BR
• Palavras-chave em Português: Fixação; Isolamento; Genética
• Palavras-chave em Inglês: Genetics
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::GENETICA::GENETICA QUANTITATIVA
• Link de acesso: http://locus.ufv.br/handle/123456789/4693

The effect of genetic drift on populations has been the subject of many studies due to a reduction in the effective population size. It may seem that the case has only effect on the genetic composition of populations. Meanwhile, a random sampling of gametes in small populations has significant consequences for the conservation of genetic diversity, as the loss of genetic diversity and fixation of alleles within the population. Genetic diversity is fundamental to the evolution. The natural selection operates between the variations within populations to adjust to the environment, providing variation among populations and, finally, variation among species. Thus, the higher the genetic variability exists in the population, the greater the chances of exploitation by breeders in their work. The maintenance of genetic variability in populations is the basis for the conservation of species and hence the description and study of the effect of genetic drift which appears on it, is reason for the search. Thus, the research aimed to analyze the effect of genetic drift on the genetic diversity of different populations. For that were generated and analyzed data from the simulation of populations. One of the key factors to evaluate the effect of genetic drift is the size of populations to be worked. To study and acquisition of genetic differentiation within and between populations under the effect of genetic drift, 4000 were simulated populations originated from molecular markers co- dominant. The samples were generated, 20, 50, 100 and 200 individuals with 100 sub-populations subjected to 10 generations of random mating with emphasis on 10 loci. The populations were evaluated with different indices of genetic diversity between and within: heterozygosity and inbreeding, Distance Shannon - Wiener (1978), Index of diversity of Nei (1973), Index of Fixing Wright (1951, 1978), heterozygosity for Weir (1996), Analysis of molecular variance (AMOVA) of Excoffier, et al., (1992). We conclude that the effect of genetic drift by changing the gene frequency depends on the size of the population. The lower the population, most obvious are the effects of random sampling, the statistics GST, FST and oST increase their value to the advancement of generations, a result of loss of genetic variation within and genetic divergence among populations.