نتایج جستجو برای: silent mutation

تعداد نتایج: 308217  

2012
John W. Drake

Until recently, the two predominant ways to estimate mutation rates were the specific-locus method and the mutation-accumulation (Bateman-Mukai) method. Both involve seeding a number of parallel lines from a small, genetically uniform population, growing as long as is feasible but not so long as to allow selection to perturb mutant frequencies, and sometimes using extreme bottlenecks to facilit...

2016
Anna Knöppel Joakim Näsvall Dan I. Andersson

Synonymous mutations do not change the sequence of the polypeptide but they may still influence fitness. We investigated in Salmonella enterica how four synonymous mutations in the rpsT gene (encoding ribosomal protein S20) reduce fitness (i.e., growth rate) and the mechanisms by which this cost can be genetically compensated. The reduced growth rates of the synonymous mutants were correlated w...

2009
Benjamin Dickins Anton Nekrutenko

Experimental evolution in rapidly reproducing viruses offers a robust means to infer substitution trajectories during evolution. But with conventional approaches, this inference is limited by how many individual genotypes can be sampled from the population at a time. Low-frequency changes are difficult to detect, potentially rendering early stages of adaptation unobservable. Here we circumvent ...

Journal: :The Journal of antimicrobial chemotherapy 2007
Erik Glocker Christian Bogdan Manfred Kist

OBJECTIVES The aim of this study was to assess the rate of rifampicin resistance in Helicobacter pylori isolated from patients in Germany, to detect rifampicin resistance-associated mutations and to identify non-resistance-associated genetic variants in the rpoB gene. METHODS Susceptibility to rifampicin in a total of 1585 clinical isolates obtained between January 2003 and July 2006 was test...

Journal: :Nucleic acids research 2003
David C Samuels Richard J Boys Daniel A Henderson Patrick F Chinnery

We applied a hidden Markov model segmentation method to the human mitochondrial genome to identify patterns in the sequence, to compare these patterns to the gene structure of mtDNA and to see whether these patterns reveal additional characteristics important for our understanding of genome evolution, structure and function. Our analysis identified three segmentation categories based upon the s...

Journal: :Genetics 2005
Carolina Bartolomé Xulio Maside Soojin Yi Anna L Grant Brian Charlesworth

We have investigated patterns of within-species polymorphism and between-species divergence for synonymous and nonsynonymous variants at a set of autosomal and X-linked loci of Drosophila miranda. D. pseudoobscura and D. affinis were used for the between-species comparisons. The results suggest the action of purifying selection on nonsynonymous, polymorphic variants. Among synonymous polymorphi...

Journal: :Genetics 2005
Kerstin Roselius Wolfgang Stephan Thomas Städler

We analyzed the effects of mating system and recombination rate on single nucleotide polymorphisms using 14 single-copy nuclear loci from single populations of five species of wild tomatoes (Solanum section Lycopersicon). The taxa investigated comprise two self-compatible (SC) and three self-incompatible (SI) species. The observed reduction in nucleotide diversity in the SC populations compared...

Journal: :AIDS research and human retroviruses 2006
Maia Zarandia Tengiz Tsertsvadze Jean K Carr Yuka Nadai Jose L Sanchez And Kenrad Nelson

The genetic diversity and genotypic drug susceptibility of HIV-1 strains circulating in the Republic of Georgia, formerly part of the Soviet Union, were investigated for first time. Forty-eight HIV-positive drug-naive Georgian individuals contributed PBMC DNA between 1998 and 2003. On the basis of phylogenetic analyses of partial pol sequences, the predominant HIV-1 genetic forms were subtype A...

2016
Marion Hartl Kristof Theys Alison Feder Maoz Gelbart Pleuni S. Pennings

HIV has a high mutation rate and exhibits remarkable genetic diversity. However, we know little about the fitness cost of HIV mutations in vivo. We calculated the mean frequency of mutations at 870 sites of the pol gene in 160 patients, allowing us to determine the cost of different types of mutations. We found that non-synonymous mutations that lead to drastic amino acid changes are three time...

Journal: :Molecular biology and evolution 1999
R Ophir T Itoh D Graur T Gojobori

We propose a method by which the intensity of purifying selection on a functional protein-coding gene is estimated by using three aligned homologous sequences: a processed pseudogene (psi), a functional paralog from the same species (g), and a functional ortholog from a different species (o). For each such trio, we calculate the numbers of nucleotide substitutions along the branches leading to ...

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