Genetics Drift
Mostrando 1-12 de 38 artigos, teses e dissertações.
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1. Diversidade e estruturação genética de Brachyteles hypoxanthus (Primates: Atelidae) em um ambiente fragmentado no município de Santa Maria de Jetibá (ES) usando DNA mitocondrial e nuclear
Brachyteles hypoxanthus, northern muriqui, is threatened by the small number of individuals in the wild, distributed in only 12 isolated populations, being classified as "critically endangered" species. Mitochondrial DNA (mtDNA) studies revealed the population of Santa Maria de Jetibá (SMJ) as a Management Unit, despite of habitat smaller and highly fragmen
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 26/02/2010
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2. Evolução do crânio dos macacos do Velho Mundo: uma abordagem de genética quantitativa / Cranial evolution of Old World monkeys and Apes: a quantitative genetics approach
This is a study on the cranial diversification of the Catarrhini, a large group of primates that includes all Old World monkeys and apes, bringing together two approaches to investigate the evolution of complex characters: quantitative genetics and morphological integration. It has three main goals: 1) to compare magnitudes and patterns of inter-trait relati
Publicado em: 2009
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3. Diversidade entre e dentro de populações simuladas sob deriva genética / Diversity among and within populations under simulated genetic drift
O efeito da deriva genética sobre as populações de pequenos tamanhos tem sido objeto de diversos estudos, apresentando efeito sobre a composição genética das populações. A amostragem dos gametas ao acaso dentro de pequenas populações com perda de diversidade genética e fixação de alelos, tem conseqüências de grande significado para a conserva�
Publicado em: 2008
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4. Dynamic processes in complex networks / Processos dinamicos em redes complexas
We study the statistical properties of in²uence networks subjected to external perturbations. We consider networks whose nodes have internal states that can assume the values 0 or 1. The internal states can change depending on the state of the neighboring nodes. We let N1 nodes be frozen in the state 1, N0 be frozen in the state 0 and the remaining N nodes
Publicado em: 2007
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5. Genetic structure and chemical defenses variaton in Brugmansia suaveolens (Solanaceae) / Estruturação genetica e variação de defesas quimicas em Brugmansia suaveolens (Solanaceae)
Populations patchily distributed tend to show high genetic structure and strong micro-evolutionary process evidences. Brugmansia suaveolens (Solanaceae) individuals are restrict to population patches. In this work, the genetic diversity of nine B. suaveolens populations was estimate by means of allozyme electrophoresis (chapter 1). Our results indicate high
Publicado em: 2006
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6. Avaliação de delineamentos genéticos em programas de melhoramento populacional recorrente, por meio de simulação / Evaluation of genetic delineation in programs of recurrent population improvement, through simulation
Comstock and Robinson (1948) have suggested the evaluation of full-sib lineages obtained by crossing m male with f female distinct groups, in order to esteem the additive components, considering the dominance of the genotypic variance, and also the average degree of dominance. This system of controlled crossings was called Delineation I. The objective of thi
Publicado em: 2006
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7. Morphological divergence rate tests for natural selection: uncertainty of parameter estimation and robustness of results
In this study, we used a combination of geometric morphometric and evolutionary genetics methods for the inference of possible mechanisms of evolutionary divergence. A sensitivity analysis for the constant-heritability rate test results regarding variation in genetic and demographic parameters was performed, in order to assess the relative influence of uncer
Genetics and Molecular Biology. Publicado em: 2005
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8. Efeito do processo dispersivo em subpopulações de tamanho reduzido de milho (Zea mays L.). / Dispersive process effect in reduced size subpopulations of maize (Zea mays L.).
The composite GN-04 was used in the present work with the objetives: a) evaluation of the effect of the dispersive process in subpopulations of maize with different effective sizes, and submitted to divergent selection for higth and low yield; b) evaluation of the combining ability and heterotic potential of the subpopulations; and c) to estimate components
Publicado em: 2004
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9. Natural Selection for within-Generation Variance in Offspring Number II. Discrete Haploid Models
In the classical model of genetic drift in population genetics theory, use is made of a hypothetical "infinite-gametic pool". If, instead, the gametic pool is determined by the random number of offspring per individual, a new form of natural selection acting on the variance in offspring number occurs. A diffusion model of this selection process is derived an
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10. Recent development of the neutral theory viewed from the Wrightian tradition of theoretical population genetics.
In contrast to the Darwinian theory of evolution by natural selection, the neutral theory emphasizes the great importance of random genetic drift (due to finite population size) and mutation pressure as the main causes of molecular evolution. In this paper, after a brief review of the neutral theory, recent data strongly supporting the neutral theory are pre
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11. Intracellular Population Genetics: Evidence for Random Drift of Mitochondrial Allele Frequencies in SACCHAROMYCES CEREVISIAE and SCHIZOSACCHAROMYCES POMBE
We report evidence for random drift of mitochondrial allele frequencies in zygote clones of Saccharomyces cerevisiae and Schizosaccharomyces pombe. Monofactorial and bifactorial crosses were done, using strains resistant or sensitive to erythromycin (alleles ER, ES), oligomycin (OR, OS), or diuron (DR, DS). The frequencies of resistant and sensitive cells (a
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12. Possibility of extensive neutral evolution under stabilizing selection with special reference to nonrandom usage of synonymous codons.
The rate of evolution in terms of the number of mutant substitutions in a finite population is investigated assuming a quantitative character subject to stabilizing selection, which is known to be the most prevalent type of natural selection. It is shown that, if a large number of segregating loci (or sites) are involved, the average selection coefficient pe