نتایج جستجو برای: positive selection

تعداد نتایج: 952965  

Journal: :Journal of evolutionary biology 2011
A Roulin S Antoniazza R Burri

Because the magnitude of selection can vary between sexes and in space and time, sexually antagonistic selection is difficult to demonstrate. In a Swiss population of barn owls (Tyto alba), a heritable eumelanic colour trait (size of black spots on ventral feathers) was positively selected with respect to yearling survival only in females. It remains unclear whether the absence of negative sele...

Journal: :Molecular biology and evolution 2008
Jeffrey D Jensen Kevin R Thornton Charles F Aquadro

A common approach for identifying loci influenced by positive selection involves scanning large portions of the genome for regions that are inconsistent with the neutral equilibrium model or represent outliers relative to the empirical distribution of some aspect of the data. Once identified, partial sequence is generated spanning this more localized region in order to quantify the site-frequen...

Journal: :Molecular biology and evolution 2005
K Scheffler C Seoighe

A popular approach to detecting positive selection is to estimate the parameters of a probabilistic model of codon evolution and perform inference based on its maximum likelihood parameter values. This approach has been evaluated intensively in a number of simulation studies and found to be robust when the available data set is large. However, uncertainties in the estimated parameter values can...

2018
T. Jeffrey Cole Michael S. Brewer

Background The recent proliferation of large amounts of biodiversity transcriptomic data has resulted in an ever-expanding need for scalable and user-friendly tools capable of answering large scale molecular evolution questions. FUSTr identifies gene families involved in the process of adaptation. This is a tool that finds genes in transcriptomic datasets under strong positive selection that au...

Journal: :Molecular biology and evolution 1993
M A Riley

To examine the hypothesis that colicin proteins are subject to diversity-enhancing selection, we studied the rates of synonymous, nonsynonymous, and intergenic nucleotide substitution in three pairs of closely related colicin clusters. The results indicate that the immunity gene and the immunity-binding domain of the colicin gene, which interact to provide specific immunity from the lethal acti...

Journal: :PLoS Genetics 2009
James J. Cai J. Michael Macpherson Guy Sella Dmitri A. Petrov

Much effort and interest have focused on assessing the importance of natural selection, particularly positive natural selection, in shaping the human genome. Although scans for positive selection have identified candidate loci that may be associated with positive selection in humans, such scans do not indicate whether adaptation is frequent in general in humans. Studies based on the reasoning o...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2014
Nicholas A Christakis James H Fowler

More than any other species, humans form social ties to individuals who are neither kin nor mates, and these ties tend to be with similar people. Here, we show that this similarity extends to genotypes. Across the whole genome, friends' genotypes at the single nucleotide polymorphism level tend to be positively correlated (homophilic). In fact, the increase in similarity relative to strangers i...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2002
Gregory M Barton Courtney Beers Paul deRoos Susan R Eastman Marcela E Gomez Katherine A Forbush Alexander Y Rudensky

If T cells require specific interactions with MHC-bound peptides during positive selection, then the specificities of T cells selected by one peptide should be distinct from those selected by another. We have examined positive selection of CD4 T cells in four strains of mice, each overexpressing a different peptide-1-A(b)(A(b)) complex. We show that a subset of CD4 T cells is selected by the ov...

2004
James Albrecht Aico van Vuuren Susan Vroman James W. Albrecht IZA Bonn

Decomposing the Gender Wage Gap in the Netherlands with Sample Selection Adjustments In this paper, we use quantile regression decomposition methods to analyze the gender gap between men and women who work full time in the Netherlands. Because the fraction of women working full time in the Netherlands is quite low, sample selection is a serious issue. In addition to shedding light on the source...

Journal: :Health services research 1990
D Haas-Wilson E Savoca

A Federal Trade Commission survey of contact lens wearers is used to estimate a multinomial logit-least-squares model of the joint determination of provider choice and quality of care in the contact lens industry. The effect of personal and industry characteristics on a consumer's choice among three types of providers--opticians, ophthalmologists, and optometrists--is estimated via multinomial ...

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