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Quasispecies
The quasispecies model is a description of the process of the Darwinian evolution of certain self-replicating entities within the framework of physical chemistry. A quasispecies is a large group or "cloud" of related genotypes that exist in an environment of high mutation rate (at stationary state), where a large fraction of offspring are expected to contain one or more mutations relative to the parent. This is in contrast to a species, which from an evolutionary perspective is a more-or-less stable single genotype, most of the offspring of which will be genetically accurate copies. It is useful mainly in providing a qualitative understanding of the evolutionary processes of self-replicating macromolecules such as RNA or DNA or simple asexual organisms such as bacteria or viruses (see also viral quasispecies), and is helpful in explaining something of the early stages of the origin of life. Quantitative predictions based on this model are difficult because the parameters that ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viral Quasispecies
A viral quasispecies is a population genetics, population structure of viruses with a large number of variant genomes (related by mutations). Quasispecies result from high mutation rates as mutants arise continually and change in relative Allele frequency, frequency as viral replication and Natural selection, selection proceeds. The theory predicts that a viral Quasispecies model, quasispecies at a low but Neutral theory of molecular evolution, evolutionarily neutral and highly connected (that is, flat) region in the fitness landscape will outcompete a quasispecies located at a higher but narrower fitness peak in which the surrounding mutants are unfit. This phenomenon has been called 'the quasispecies effect' or, more recently, the 'survival of the flattest'. The term quasispecies was adopted from a theory of the origin of life in which primitive Replicon (genetics), replicons consisted of mutant distributions, as found experimentally with present-day RNA viruses within their Hos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour, or ecological niche. In addition, palaeontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. About 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomen". The first part of a binomen is the name of a genus to which the species belongs. The second part is called the specific name (zoology), specific name or the specific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Error Threshold (evolution)
In evolutionary biology and population genetics, the error threshold (or critical mutation rate) is a limit on the number of base pairs a self-replicating molecule may have before mutation will destroy the information in subsequent generations of the molecule. The error threshold is crucial to understanding "Eigen's paradox". The error threshold is a concept in the origins of life (abiogenesis), in particular of very early life, before the advent of DNA. It is postulated that the first self-replicating molecules might have been small ribozyme-like RNA molecules. These molecules consist of strings of base pairs or "digits", and their order is a code that directs how the molecule interacts with its environment. All replication is subject to mutation error. During the replication process, each digit has a certain probability of being replaced by some other digit, which changes the way the molecule interacts with its environment, and may increase or decrease its fitness, or ability ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gard Model
In evolutionary biology, the GARD (Graded Autocatalysis Replication Domain) model is a general kinetic model for homeostatic-growth and fission of compositional-assemblies, with specific application towards lipids. In the context of abiogenesis, the lipid-world suggests assemblies of simple molecules, such as lipids, can store and propagate information, and thus undergo evolution. These 'compositional assemblies' have been suggested to play a role in the origin of life. The idea is the information being transferred throughout the generations is '' compositional information '' – the different types and quantities of molecules within an assembly. This is different from the information encoded in RNA or DNA, which is the specific sequence of bases in such molecule. Thus, the model is viewed as an alternative or an ancestor to the RNA world hypothesis. The model The composition vector of an assembly is written as: v=n_1\cdots n_. Where n_1\cdots n_ are the molecular counts of lip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emmanuel David Tannenbaum
Emmanuel David Tannenbaum (; June 28, 1978 – May 28, 2012) was an Israeli/American biophysicist and applied mathematician. He worked as a professor and researcher in the department of chemistry at the Ben-Gurion University of the Negev and the department of biology at the Georgia Institute of Technology, specializing in the fields of mathematical biology, systems biology, and quantum physics. Tannenbaum's initial work was in quantum chemistry as part of his Harvard University doctoral thesis where he developed a novel partial differential equation approach to the EBK quantization of nearly separable Hamiltonians in the quasi-integrable regime. Emmanuel Tannenbaum subsequently devoted his research to studying various problems in evolutionary dynamics using quasispecies models. His seminal work centered on the key question of the evolutionary advantages of sexual reproduction. Tannenbaum demonstrated a strong selective advantage for sexual reproduction with fewer and much less res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virus
A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are found in almost every ecosystem on Earth and are the most numerous type of biological entity. Since Dmitri Ivanovsky's 1892 article describing a non-bacterial pathogen infecting tobacco plants and the discovery of the tobacco mosaic virus by Martinus Beijerinck in 1898, more than 16,000 of the millions of List of virus species, virus species have been described in detail. The study of viruses is known as virology, a subspeciality of microbiology. When infected, a host cell is often forced to rapidly produce thousands of copies of the original virus. When not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent viral particles, or ''virions'', consisting of (i) genetic material, i.e., long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter Schuster
Peter K. Schuster (born 7 March 1941) is a theoretical chemist known for his work with the German Nobel Laureate Manfred Eigen in developing the quasispecies model. His work has made great strides in the understanding of viruses and their replication, as well as theoretical mechanisms in the origin of life. Biography Schuster was born in Vienna, Austria and graduated with highest honors from "gymnasium". He studied chemistry and physics at the University of Vienna and earned his PhD in 1967. He was a Postdoc at the Max Planck Institute for Biophysical Chemistry. Together with Eigen, Schuster developed the quasispecies model. He is full professor of theoretical chemistry at the University of Vienna, the founding director of the Institute of Molecular Biotechnology in Jena, Germany, as well as the current head of its Department of Molecular Evolutionary Biology. He is an external faculty member at the Santa Fe Institute. Currently, Prof. Schuster is the President of the Austria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manfred Eigen
Manfred Eigen (; 9 May 1927 – 6 February 2019) was a German biophysical chemist who won the 1967 Nobel Prize in Chemistry for work on measuring fast chemical reactions. Eigen's research helped solve major problems in physical chemistry and aided in the understanding of chemical processes that occur in living organisms. In later years, he explored the biochemical roots of life and evolution. He worked to install a multidisciplinary program at the Max Planck Institute to study the underpinnings of life at the molecular level. His work was hailed for creating a new scientific and technological discipline: evolutionary biotechnology. Education and early life Eigen was born on 9 May 1927 in Bochum, the son of Ernst and Hedwig (Feld) Eigen, a chamber musician. As a child he developed a deep passion for music, and studied piano. World War II interrupted his formal education. At age fifteen he was drafted into service in a German antiaircraft unit. He was captured by the America ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eigenvectors
In linear algebra, an eigenvector ( ) or characteristic vector is a Vector (mathematics and physics), vector that has its direction (geometry), direction unchanged (or reversed) by a given linear map, linear transformation. More precisely, an eigenvector \mathbf v of a linear transformation T is scalar multiplication, scaled by a constant factor \lambda when the linear transformation is applied to it: T\mathbf v=\lambda \mathbf v. The corresponding eigenvalue, characteristic value, or characteristic root is the multiplying factor \lambda (possibly a negative number, negative or complex number, complex number). Euclidean vector, Geometrically, vectors are multi-dimensional quantities with magnitude and direction, often pictured as arrows. A linear transformation Rotation (mathematics), rotates, Scaling (geometry), stretches, or Shear mapping, shears the vectors upon which it acts. A linear transformation's eigenvectors are those vectors that are only stretched or shrunk, with nei ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the Heredity, heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which is intentional, whereas natural selection is not. Genetic diversity, Variation of traits, both Genotype, genotypic and phenotypic, exists within all populations of organisms. However, some traits are more likely to facilitate survival and reproductive success. Thus, these traits are passed the next generation. These traits can also become more Allele frequency, common within a population if the environment that favours these traits remains fixed. If new traits become more favoured due to changes in a specific Ecological niche, niche, microevolution occurs. If new traits become more favoured due to changes in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primitive Matrix
Primitive may refer to: Mathematics * Primitive element (field theory) * Primitive element (finite field) * Primitive cell (crystallography) * Primitive notion, axiomatic systems * Primitive polynomial (other), one of two concepts * Primitive function or antiderivative, ' = ''f'' * Primitive permutation group * Primitive root of unity; See Root of unity * Primitive triangle, an integer triangle whose sides have no common prime factor Sciences * Primitive (phylogenetics), characteristic of an early stage of development or evolution * Primitive equations, a set of nonlinear differential equations that are used to approximate atmospheric flow * Primitive change, a general term encompassing a number of basic molecular alterations in the course of a chemical reaction Computing * Cryptographic primitives, low-level cryptographic algorithms frequently used to build computer security systems * Geometric primitive, the simplest kinds of figures in computer graphics * Language prim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eigenvalues
In linear algebra, an eigenvector ( ) or characteristic vector is a vector that has its direction unchanged (or reversed) by a given linear transformation. More precisely, an eigenvector \mathbf v of a linear transformation T is scaled by a constant factor \lambda when the linear transformation is applied to it: T\mathbf v=\lambda \mathbf v. The corresponding eigenvalue, characteristic value, or characteristic root is the multiplying factor \lambda (possibly a negative or complex number). Geometrically, vectors are multi-dimensional quantities with magnitude and direction, often pictured as arrows. A linear transformation rotates, stretches, or shears the vectors upon which it acts. A linear transformation's eigenvectors are those vectors that are only stretched or shrunk, with neither rotation nor shear. The corresponding eigenvalue is the factor by which an eigenvector is stretched or shrunk. If the eigenvalue is negative, the eigenvector's direction is reversed. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
