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Topic: Neutral theory of molecular evolution


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  Neutral theory of molecular evolution - Wikipedia, the free encyclopedia
The neutral theory of molecular evolution (also, simply the neutral theory of evolution) is an influential theory that was introduced with provocative effect by Motoo Kimura in the late 1960s and early 1970s.
Although the theory was received by some as an argument against Darwin's theory of evolution by natural selection, Kimura and most evolutionary biologists today maintain that the two theories are compatible.
Many molecular biologists and population geneticists, besides Kimura, contributed to the development of the neutral theory, which may be viewed as an offshoot of the modern evolutionary synthesis.
en.wikipedia.org /wiki/Neutral_theory_of_molecular_evolution   (1012 words)

  
 Neutral theory of molecular evolution   (Site not responding. Last check: 2007-11-07)
A second assertion or hypothesis of the neutral theory is that most evolutionary change is the result of genetic drift acting on neutral allele s.
Tomoko Ohta extended the neutral theory to include the concept of "near-neutrality", that is, genes that are affected mostly by drift or mostly by selection depending on the effective size of a breeding population.
The Society for Molecular Biology and Evolution Is an international society that exists to provide facilities for association and communication among molecular evolutionists, and has as one of its primary goals increasing communication between the fields of evolution and molecular biology.
www.serebella.com /encyclopedia/article-Neutral_theory_of_molecular_evolution.html   (1265 words)

  
 Neutral theory of molecular evolution: Definition and Links by Encyclopedian.com - All about Neutral theory of ...   (Site not responding. Last check: 2007-11-07)
According to Kimura, when one compares the genomes of existing species, or looks between a species and its forebears, the vast majority of single-nucleotide differences are selectively "neutral." That is, these differences do not influence the fitness of either the species or the individuals who make up the species.
Many molecular biologists and population geneticists, besides Kimura, contributed to the development of the neutral theory, which may be viewed as an offshoot of the modern synthesis.
In such a test, the number of differences that exist between two actual sequences is compared to the number that the neutral theory predicts, given the assumption of a certain elapsed time since the species diverged (typically measured from fossil records or historical records in the case of shorter time intervals).
www.encyclopedian.com /ne/Neutral-theory-of-evolution.html   (780 words)

  
 Talk:Neutral theory of molecular evolution - Wikipedia, the free encyclopedia
When I wrote "The neutral theory is closely tied to and rests in part on the theory of genetic drift," what I meant was that the theory draws on the mathematics and principles of genetic drift,and that the phenomenon it describes is an elaboration on drift that includes drift.
Drift is an observable phenomena, not a theory.
The theory that the "Neutral Theory" relies on is the modern synthesis.
en.wikipedia.org /wiki/Talk:Neutral_theory_of_molecular_evolution   (6633 words)

  
 Evolution - Molecular evolution and neutral theory
The neutral theory of molecular evolution is that most evolutionary change at the molecular level is driven by random drift rather than natural selection.
The neutral theory does not suggest that random drift explains all evolutionary change: natural selection is still needed to explain adaptation.
However, the neutral theory states that evolution at the level of the DNA and proteins, but not of morphology, is dominated by random processes; most evolution at the molecular level would then be non-adaptive.
www.blackwellpublishing.com /ridley/tutorials/Molecular_evolution_and_neutral_theory2.asp   (227 words)

  
 Neutral theory of molecular evolution   (Site not responding. Last check: 2007-11-07)
The neutral theory of molecular evolution (also simply the neutral theory of evolution) is an influential theory that was with provocative effect by Motoo Kimura in late 1960s and early 1970s.
Although the theory was received by as an argument against Darwin's theory of evolution by natural selection Kimura and most evolutionary biologists today that the two theories are compatible.
Tomoko Ohta extended the neutral theory to the concept of "near-neutrality" that is genes are affected mostly by drift or mostly selection depending on the effective size of breeding population.
www.freeglossary.com /Neutral_theory_of_molecular_evolution   (795 words)

  
 Neutral theory of molecular evolution   (Site not responding. Last check: 2007-11-07)
Thus, theneutral theory is the foundation of the molecular clock technique,which evolutionary molecular biologists use to measure how much time has passed since speciesdiverged from a common ancestor.
Many molecular biologists and population geneticists, besides Kimura, contributed to thedevelopment of the neutral theory, which may be viewed as an offshoot of the modern evolutionary synthesis.
As of the early 2000s, the neutral theory is widely used as a "null model" forso-called null hypothesis testing.
www.therfcc.org /neutral-theory-of-molecular-evolution-45053.html   (727 words)

  
 Evolution: Library: Molecular Evolution: Neutral Drift
One hypothesis suggests that most molecular evolution is driven by random changes in genes, or "neutral drift." The other proposes that natural selection favoring beneficial variations in an organism's genes is the primary mechanism.
That is, changes affect the "letters" (four different types of chemical units) in the genetic blueprints -- the genes -- that are carried in their cells.
Even individuals that look and appear to be the same may be distinctively different because of variations in their genetic code at different places on their chromosomes (the structures that carry the genes).
www.pbs.org /wgbh/evolution/library/05/1/l_051_04.html   (554 words)

  
 The neutral theory of molecular evolution. (Motoo Kimura).
Kimura's 'Neutral Theory' got a firm place in the standard textbooks (2) on evolution and population genetics, despite being clearly anti-selectionist.
Molecular variation in proteins and DNA was uncovered that had no influence on the fitness of the individual organism: in other words: is selectively neutral.
Please note that 'the neutral theory of evolution' is not sufficient to explain complex life and adaptations.
home.planet.nl /~gkorthof/kortho37.htm   (1412 words)

  
 Scientists Find No Genetic Evidence For Evolution
Critics of Darwin's theory of evolution point to flaws in the fossil record (no new species, no missing links) as evidence that the theory is false.
The authors of the research conclude that the neutral theory of molecular evolution (predictable or constant rates of change) is flawed and that changes in the rate of variation are left to the vagaries of natural selection (randomness).
The so-called neutral theory of evolution holds that DNA mutations (protein substitutions) accumulate at an approximately constant rate as long as the DNA retains its original functions.
www.lewrockwell.com /orig/sardi5.html   (811 words)

  
 Molecular Evolution
Two general approaches to molecular evolution are to 1) use DNA to study the evolution of organisms (such as population structure, geographic variation and systematics) and to 2) to use different organisms to study the evolution of DNA.
Our general goal in all this is to infer process from pattern and this applies to the processes of organismal evolution deduced from patterns of DNA variation, and processes of molecular evolution inferred from the patterns of variation in the DNA itself.
To describe molecular evolution Kimura formulated the Neutral theory of molecular evolution which is remarkably simple.
biomed.brown.edu /Courses/BIO48/12.Molecular.Evolution.HTML   (2443 words)

  
 The Neutral Theory of Molecular Evolution - Cambridge University Press   (Site not responding. Last check: 2007-11-07)
He first proposed the theory in 1968 to explain the unexpectedly high rate of evolutionary change and very large amount of intraspecific variability at the molecular level that had been uncovered by new techniques in molecular biology.
Overdevelopment of the synthetic theory and the proposal of the neutral theory; 3.
The neutral mutation-random drift hypothesis as an evolutionary paradigm; 4.
www.cambridge.org /uk/catalogue/catalogue.asp?isbn=0521317932   (321 words)

  
 General Models of Evolution
This assumption agrees with the mutational molecular substitution rate observed experimentally and with the fact that the rate of the substitutions for the less biologically important part of macromolecules is greater than for the active macromolecule centers.
The mathematical models of the neutral theory are essentially stochastic, that is, a relatively small population size plays an important role in the fixation of the neutral mutations.
The evolutionary concepts of the neutral theory came from interpretations of biological experiments; this theory was strongly empirically inspired.
pespmc1.vub.ac.be /GENMODEV.html   (533 words)

  
 The neutrality theory of molecular evolution (from evolution) --¬† Encyclop√¶dia Britannica
theory in biology postulating that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations.
The theory of evolution is one of the fundamental keystones of modern biological theory.
The theory's evolution in the 19th century was preceded by more than two centuries of observations of small life forms under the microscope.
www.britannica.com /eb/article-49906   (904 words)

  
 Survival of the Fittest Molecules
According to the neutral theory of molecular evolution, in comparing the genomes of two different species the ratio between amino acid polymorphisms (DNA differences that impact proteins) and synonymous polymorphisms (DNA differences that have no effect on proteins) should equal the amino-acid-synonymous (A/S)ratio in genetic divergence.
If the neutral theory is correct, then changes in DNA and amino acid sequences should be relatively constant, and the amount of polymorphism within a single species should be proportional to the amount of divergence between two different species.
This means there should be a "molecular clock" of protein evolution that could be used to date the divergence between different species by comparing differences in their DNA and amino acid sequences.
www.lbl.gov /Science-Articles/Archive/LSD-fittest-molecules-Fay.html   (763 words)

  
 Citations: The Neutral Theory of Molecular Evolution - Kimura (ResearchIndex)   (Site not responding. Last check: 2007-11-07)
Citations: The Neutral Theory of Molecular Evolution - Kimura (ResearchIndex)
Neutral evolution and molecular evolutionary biology The notion of neutral evolution was coined by Motoo Kimura
The conventional neutral theory, however, is dealing with the evolution of rather complex organisms and cannot provide direct insight into molecular....
citeseer.ist.psu.edu /context/40391/0   (1442 words)

  
 Evolution II   (Site not responding. Last check: 2007-11-07)
Kimura, M. 1983 The Neutral Theory of Molecular Evolution Cambridge University Press Consider new alleles brought into a population by mutation: 1.
Neutral mutations If neutral mutations occur at a rate of u per gene per generation, then the number of mutants arising in a diploid population of size N is 2Nu per generation.
Therefore, if the neutral mutation hypothesis is true and if the rate of neutral (or nearly neutral mutation) in a protein has not changed with time, the rate of evolution in that protein should be nearly constant.
eebweb.arizona.edu /Courses/Ecol435_535/Oct5.htm   (1341 words)

  
 Evolution 101: Neutral Theory
But the neutral theory of molecular evolution suggests that most of the genetic variation in populations is the result of mutation and genetic drift and not selection.
Basically, the theory suggests that if a population carries several different versions of a gene, odds are that each of those versions is equally good at performing its job—in other words, that variation is neutral: whether you carry gene version A or gene version B does not affect your fitness.
The main point of the neutral theory is simply that when we see several versions of a gene in a population, it is likely that their frequencies are simply drifting around.
evolution.berkeley.edu /evosite/evo101/IIIE5bNeutraltheory.shtml   (202 words)

  
 Testing the Neutral Theory of Molecular Evolution: Understanding the MacDonald-Kreitman Test   (Site not responding. Last check: 2007-11-07)
MacDonald and Kreitman (1991) propose a test of the neutral mutation-random drift (NM-RD) hypothesis, the central claim of the neutral theory of molecular evolution.
Neutral changes fix slowly by genetic drift, whereas non-neutral changes will either increase in frequency quickly or be eliminated by selection.
The equations for determining the numbers of fixed differences and polymorphisms predicted by the neutral theory for both replacement and synonymous regions of a gene.
www.stanford.edu /~pforber/MKtest-conversion.html   (2186 words)

  
 Molecular evolution bibliography
Baltscheffsky, H., 1981, Stepwise molecular evolution of bacterial photosynthetic energy conversion: BioSystems, v.
Follmann, H., 1982, Deoxyribonucleotide systhesis and the emergence of DNA in molecular evolution: Naturwissenschaften, v.
Sibley, C., and Ahlquist, J., 1984, The phylogeny of the homonid primates as indicated by DNA-DNA hybridization: Journal of Molecular Evolution, v.
www.talkorigins.org /origins/biblio/molecular_evolution.html   (579 words)

  
 CA611: Evolution sacrosanct?
Neutral theory, proposing that most generic variation is neutral, not subject to selection (or nearly neutral, in Ohta's extension of the theory; Kimura 1983; Ohta 1992).
Evolution has undergone a tremendous amount of testing, some of which has shown that correction is necessary.
Critics of evolution are treated as intellectual outcasts not because they criticize evolution but because they do not know what they are talking about.
www.talkorigins.org /indexcc/CA/CA611.html   (534 words)

  
 MOLECULAR EVOLUTION   (Site not responding. Last check: 2007-11-07)
The driving force of molecular evolution is random fixations of neutral mutations rather than natural selection fixing advantageous mutations.
The Neutral Theory does not claim that all mutations are neutral.
The hypothesis of molecular clock asserts that the rate of DNA or protein sequence evolution is constant over time or among evolutionary lineages.
www.mrc-lmb.cam.ac.uk /genomes/cvogel/Tutorials/MolEvol.htm   (463 words)

  
 Biology430.Lectures6
Rather, he argued that most alleles are selectively neutral (or nearly so), and that the fate of alleles is determined by the interaction of mutation and random genetic drift.
Kimura did not argue that all mutations are selectively neutral, and that selection does not play an important role in shaping many characteristics of organisms, only that these cases represent the minority of changes occuring at the molecular level.
Probably the most important practical consequence of the neutral model is the idea that molecular evolution should be relatively clocklike.
bioweb.wku.edu /courses/Biol430/430lects6.htm   (719 words)

  
 The Neutral Theory of Molecular Evolution   (Site not responding. Last check: 2007-11-07)
The Neutral Theory of Molecular Evolution Review: "Natural" mathematics is the idea that mathematical formulations are inherently prone to paradox.
Kimura's neutral theory used to be regarded as the dernier mot in avant garde biological theory.
It is very likely that Kimura's notion of "population" plays the same role in the neutral theory, that set E plays in Richard's contradiction, and this identification invalidates the neutral theory.
www.textkit.com /0_0521317932.html   (379 words)

  
 The Infography about Molecular Evolution
The following sources are recommended by a professor whose research specialty is molecular evolution.
The effect of deleterious mutations on neutral molecular variation.
Kimura, M. The neutral allele theory of molecular evolution.
www.infography.com /content/637893575540.html   (117 words)

  
 Kimura, Motoo: Population Genetics, Molecular Evolution, and the Neutral Theory
Kimura, Motoo: Population Genetics, Molecular Evolution, and the Neutral Theory
Kimura's neutral theory, first presented in 1968, challenged the notion that natural selection was the sole directive force in evolution.
This volume includes the seminal papers on the neutral theory, as well as many others that cover such topics as population structure, variable selection intensity, the genetics of quantitative characters, inbreeding systems, and reversibility of changes by random drift.
www.press.uchicago.edu /cgi-bin/hfs.cgi/00/12702.ctl   (898 words)

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