The Experts below are selected from a list of 228699 Experts worldwide ranked by ideXlab platform
Marcus W Feldman - One of the best experts on this subject based on the ideXlab platform.
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the power of randomization by sex in multilocus Genetic Evolution
Biology Direct, 2020Co-Authors: Liudmyla Vasylenko, Marcus W Feldman, Adi LivnatAbstract:BACKGROUND Many hypotheses have been proposed for how sexual reproduction may facilitate an increase in the population mean fitness, such as the Fisher-Muller theory, Muller's ratchet and others. According to the recently proposed mixability theory, however, sexual recombination shifts the focus of natural selection away from favoring particular Genetic combinations of high fitness towards favoring alleles that perform well across different Genetic combinations. Mixability theory shows that, in finite populations, because sex essentially randomizes Genetic combinations, if one allele performs better than another across the existing combinations of alleles, that allele will likely also perform better overall across a vast space of untested potential genotypes. However, this superiority has been established only for a single-locus diploid model. RESULTS We show that, in both haploids and diploids, the power of randomization by sex extends to the multilocus case, and becomes substantially stronger with increasing numbers of loci. In addition, we make an explicit comparison between the sexual and asexual cases, showing that sexual recombination is the cause of the randomization effect. CONCLUSIONS That the randomization effect applies to the multilocus case and becomes stronger with increasing numbers of loci suggests that it holds under realistic conditions. One may expect, therefore, that in nature the ability of an allele to perform well in interaction with existing Genetic combinations is indicative of how well it will perform in a far larger space of potential combinations that have not yet materialized and been tested. Randomization plays a similar role in a statistical test, where it allows one to draw an inference from the outcome of the test in a small sample about its expected outcome in a larger space of possibilities-i.e., to generalize. Our results are relevant to recent theories examining Evolution as a learning process. REVIEWERS This article was reviewed by David Ardell and Brian Golding.
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cultural Evolutionary theory how culture evolves and why it matters
Proceedings of the National Academy of Sciences of the United States of America, 2017Co-Authors: Nicole Creanza, Oren Kolodny, Marcus W FeldmanAbstract:Human cultural traits—behaviors, ideas, and technologies that can be learned from other individuals—can exhibit complex patterns of transmission and Evolution, and researchers have developed theoretical models, both verbal and mathematical, to facilitate our understanding of these patterns. Many of the first quantitative models of cultural Evolution were modified from existing concepts in theoretical population Genetics because cultural Evolution has many parallels with, as well as clear differences from, Genetic Evolution. Furthermore, cultural and Genetic Evolution can interact with one another and influence both transmission and selection. This interaction requires theoretical treatments of gene–culture coEvolution and dual inheritance, in addition to purely cultural Evolution. In addition, cultural Evolutionary theory is a natural component of studies in demography, human ecology, and many other disciplines. Here, we review the core concepts in cultural Evolutionary theory as they pertain to the extension of biology through culture, focusing on cultural Evolutionary applications in population Genetics, ecology, and demography. For each of these disciplines, we review the theoretical literature and highlight relevant empirical studies. We also discuss the societal implications of the study of cultural Evolution and of the interactions of humans with one another and with their environment.
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the application of molecular Genetic approaches to the study of human Evolution
Nature Genetics, 2003Co-Authors: L L Cavallisforza, Marcus W FeldmanAbstract:doi:10.1038/ng1113 The past decade of advances in molecular Genetic technology has heralded a new era for all Evolutionary studies, but especially the science of human Evolution. Data on various kinds of DNA variation in human populations have rapidly accumulated. There is increasing recognition of the importance of this variation for medicine and developmental biology and for understanding the history of our species. Haploid markers from mitochondrial DNA and the Y chromosome have proven invaluable for generating a standard model for Evolution of modern humans. Conclusions from earlier research on protein polymorphisms have been generally supported by more sophisticated DNA analysis. Co-Evolution of genes with language and some slowly evolving cultural traits, together with the Genetic Evolution of commensals and parasites that have accompanied modern humans in their expansion from Africa to the other continents, supports and supplements the standard model of Genetic Evolution. The advances in our understanding of the Evolutionary history of humans attests to the advantages of multidisciplinary research. review
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niche construction and gene culture coEvolution an Evolutionary basis for the human sciences
2000Co-Authors: John F Odlingsmee, Kevin N Laland, Marcus W FeldmanAbstract:Traditionally Evolutionary theory treats the adaptations of organisms as consequences of a process whereby natural selection moulds organisms to fit pre-established environments. The changes that organisms themselves cause in their own environments are seldom through to be Evolutionarily significant. However, active organisms partly create their own selective environments by “niche construction,” and ancestral organisms can pass on legacies of modified natural selection pressures in their environments to their descendants. In this chapter, we build on conventional Evolutionary theory by adding niche construction. We argue that the resulting enhanced theory of Evolution provides a better basis for understanding how human cultural processes interact with human Genetic processes in human Evolution, and we discuss how human cultural niche construction may have co-directed, and may still be co-directing, human Genetic Evolution.
Adam Rash - One of the best experts on this subject based on the ideXlab platform.
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antigenic and Genetic Evolution of equine influenza a h3n8 virus from 1968 to 2007
Journal of Virology, 2011Co-Authors: Nicola S. Lewis, David F. Burke, Colin A Russell, Eugene Skepner, Janet M Daly, Daniel L Horton, Neil Bryant, Adam RashAbstract:Equine influenza virus is a major respiratory pathogen in horses, and outbreaks of disease often lead to substantial disruption to and economic losses for equestrian industries. The hemagglutinin (HA) protein is of key importance in the control of equine influenza because HA is the primary target of the protective immune response and the main component of currently licensed influenza vaccines. However, the influenza virus HA protein changes over time, a process called antigenic drift, and vaccine strains must be updated to remain effective. Antigenic drift is assessed primarily by the hemagglutination inhibition (HI) assay. We have generated HI assay data for equine influenza A (H3N8) viruses isolated between 1968 and 2007 and have used antigenic cartography to quantify antigenic differences among the isolates. The antigenic Evolution of equine influenza viruses during this period was clustered: from 1968 to 1988, all isolates formed a single antigenic cluster, which then split into two cocirculating clusters in 1989, and then a third cocirculating cluster appeared in 2003. Viruses from all three clusters were isolated in 2007. In one of the three clusters, we show evidence of antigenic drift away from the vaccine strain over time. We determined that a single amino acid substitution was likely responsible for the antigenic differences among clusters.
Donald E Irwin - One of the best experts on this subject based on the ideXlab platform.
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The role of phenotypic plasticity in driving Genetic Evolution
Proceedings of the Royal Society B: Biological Sciences, 2003Co-Authors: T D Price, Anna Qvarnström, Donald E IrwinAbstract:Models of population divergence and speciation are often based on the assumption that differences between populations are due to Genetic factors, and that phenotypic change is due to natural selection. It is equally plausible that some of the differences among populations are due to phenotypic plasticity. We use the metaphor of the adaptive landscape to review the role of phenotypic plasticity in driving Genetic Evolution. Moderate levels of phenotypic plasticity are optimal in permitting population survival in a new environment and in bringing populations into the realm of attraction of an adaptive peak. High levels of plasticity may increase the probability of population persistence but reduce the likelihood of Genetic change, because the plastic response itself places the population close to a peak. Moderate levels of plasticity arise whenever multiple traits, some of which are plastic and others not, form a composite trait involved in the adaptive response. For example, altered behaviours may drive selection on morphology and physiology. Because there is likely to be a considerable element of chance in which behaviours become established, behavioural change followed by morphological and physiological Evolution may be a potent force in driving Evolution in novel directions. We assess the role of phenotypic plasticity in stimulating Evolution by considering two examples from birds: (i) the Evolution of red and yellow plumage coloration due to carotenoid consumption; and (ii) the Evolution of foraging behaviours on islands. Phenotypic plasticity is widespread in nature and may speed up, slow down, or have little effect on Evolutionary change. Moderate levels of plasticity may often facilitate Genetic Evolution but careful analyses of individual cases are needed to ascertain whether plasticity has been essential or merely incidental to population differentiation.
Colin A Russell - One of the best experts on this subject based on the ideXlab platform.
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antigenic and Genetic Evolution of equine influenza a h3n8 virus from 1968 to 2007
Journal of Virology, 2011Co-Authors: Nicola S. Lewis, David F. Burke, Colin A Russell, Eugene Skepner, Janet M Daly, Daniel L Horton, Neil Bryant, Adam RashAbstract:Equine influenza virus is a major respiratory pathogen in horses, and outbreaks of disease often lead to substantial disruption to and economic losses for equestrian industries. The hemagglutinin (HA) protein is of key importance in the control of equine influenza because HA is the primary target of the protective immune response and the main component of currently licensed influenza vaccines. However, the influenza virus HA protein changes over time, a process called antigenic drift, and vaccine strains must be updated to remain effective. Antigenic drift is assessed primarily by the hemagglutination inhibition (HI) assay. We have generated HI assay data for equine influenza A (H3N8) viruses isolated between 1968 and 2007 and have used antigenic cartography to quantify antigenic differences among the isolates. The antigenic Evolution of equine influenza viruses during this period was clustered: from 1968 to 1988, all isolates formed a single antigenic cluster, which then split into two cocirculating clusters in 1989, and then a third cocirculating cluster appeared in 2003. Viruses from all three clusters were isolated in 2007. In one of the three clusters, we show evidence of antigenic drift away from the vaccine strain over time. We determined that a single amino acid substitution was likely responsible for the antigenic differences among clusters.
Daniel L Horton - One of the best experts on this subject based on the ideXlab platform.
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antigenic and Genetic Evolution of equine influenza a h3n8 virus from 1968 to 2007
Journal of Virology, 2011Co-Authors: Nicola S. Lewis, David F. Burke, Colin A Russell, Eugene Skepner, Janet M Daly, Daniel L Horton, Neil Bryant, Adam RashAbstract:Equine influenza virus is a major respiratory pathogen in horses, and outbreaks of disease often lead to substantial disruption to and economic losses for equestrian industries. The hemagglutinin (HA) protein is of key importance in the control of equine influenza because HA is the primary target of the protective immune response and the main component of currently licensed influenza vaccines. However, the influenza virus HA protein changes over time, a process called antigenic drift, and vaccine strains must be updated to remain effective. Antigenic drift is assessed primarily by the hemagglutination inhibition (HI) assay. We have generated HI assay data for equine influenza A (H3N8) viruses isolated between 1968 and 2007 and have used antigenic cartography to quantify antigenic differences among the isolates. The antigenic Evolution of equine influenza viruses during this period was clustered: from 1968 to 1988, all isolates formed a single antigenic cluster, which then split into two cocirculating clusters in 1989, and then a third cocirculating cluster appeared in 2003. Viruses from all three clusters were isolated in 2007. In one of the three clusters, we show evidence of antigenic drift away from the vaccine strain over time. We determined that a single amino acid substitution was likely responsible for the antigenic differences among clusters.