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Topic: Mutation rate

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  Mutation - Wikipedia, the free encyclopedia
Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses, or can occur deliberately under cellular control during the processes such as meiosis or hypermutation.
Mutations are considered the driving force of evolution, where less favorable (or deleterious) mutations are removed from the gene pool by natural selection, while more favorable (or beneficial) ones tend to accumulate.
Neutral mutations do not affect the organism's chances of survival in its natural environment and can accumulate over time, which might result in what is known as punctuated equilibrium, a disputed interpretation of the fossil record.
en.wikipedia.org /wiki/Mutation   (1429 words)

These mutations, in contrast to the somatic mutations, will be passed on to the next generation, because they occur in the cells that produce the next generation.
Induced mutations can only be discerned by looking at the mutation rate in a population, and comparing it to the spontaneous mutation rate for the species.
A mutation may occur in a gene that encodes an enzyme involved in a metabolic pathway, such as an enzyme involved in the biosynthesis of an amino acid.
www.emunix.emich.edu /~rwinning/genetics/mutat.htm   (975 words)

 ipedia.com: Mutation Article   (Site not responding. Last check: 2007-11-06)
Mutations (or mutagenesis, both words originating in the Latin word mutare, to change) are permanent, transmissible changes to the genetic material (usually DNA or RNA) of an organism.
Mutations can be caused by copying errors in the genetic material during cell division and by exposure to radiation, chemicals, or viruses.
Mutations are considered the driving force of evolution, where less favorable mutations are removed by natural selection, but favorable ones tend to accumulate.
www.ipedia.com /mutation.html   (604 words)

 mutation. The Columbia Encyclopedia, Sixth Edition. 2001-05   (Site not responding. Last check: 2007-11-06)
Sometimes the word mutation is used broadly to include variations resulting from aberrations of chromosomes; in chromosomal mutations the number of chromosomes may be altered, or segments of chromosomes may be lost or rearranged.
For example, the inherited sickle cell disease is the result of a mutation that results in the substitution of the amino acid valine for glutamic acid in hemoglobin.
Mutations may be induced by exposure to ultraviolet rays and alpha, beta, gamma, and X radiation, by extreme changes in temperature, and by certain mutagenic chemicals such as nitrous acid, nitrogen mustard, and chemical substitutes for portions of the nucleotide subunits of genes.
www.bartleby.com /65/mu/mutation.html   (563 words)

 Mutation, Mutagens, and DNA Repair
Mutations, or heritable alterations in the genetic material, may be gross (at the level of the chromosome, which we have already discussed) or point alterations (this technically means mutations not visible as cytological abnormalities and/or those which map to a single "point" in experimental crosses).
Missense mutations may have very serious consquences, as in the case of sickle-cell anemia, mild consequences as in the case of hemoglobin C (a different amino acid substitution in position 6 of beta-globin) or no phenotype as in the case of two known amino acid substitutions at position 7 of beta-globin.
Mutator mutants have since been isolated in other organisms and have been shown to affect various components of the DNA replication complex; alterations in a number of these proteins are likely to affect the accuracy of the system.
www-personal.ksu.edu /~bethmont/mutdes.html   (4992 words)

 The Effects of Mutation Rate Modulation on GAs Utilizing the Election Operator   (Site not responding. Last check: 2007-11-06)
Reproduction of the rate strings is effected in the normal way: probability of reproduction is based on that rate string's fitness relative to the aggregate fitness of the population of rate strings.
Mutation of the rate-strings is done at a constant probability of 0.0033.
The mutation rate applied depends on the degree of convergence of the string population.
www.ugcs.caltech.edu /~baldeep/ec101/setup.shtml   (497 words)

 DNA Mutation Rates - An Overview and Discussion
And a recent study by FamilyTreeDNa indicates that the average mutation rate for all Y-STR markers for the male population as a whole may be twice as fast as the historical standard rate, i.e.,.004 or 0.4% instead of.002 or 0.2%.
Even the mutation rate for the entire Y chromosome molecule located in the cell nucleus can be estimated although typing the entire molecule is not economically practical at this time because of its large size (about 60,000,000 nucleotides).
For example, in my Kerchner Surname Project the average mutation rate is.0025 for the 12 marker haplotype,.0047 for the 25 marker haplotype, and.0056 for the 37 marker haplotype for nine related participants in three independent descendant branches from the common male ancestor who was known by prior traditional genealogical research and family history.
www.kerchner.com /dnamutationrates.htm   (4267 words)

 UF Study: Similar Species Can Show Different Rates Of Genetic Mutation - UF 2 Go   (Site not responding. Last check: 2007-11-06)
Understanding the variability in the baseline mutation rate for closely related species is also an essential first step toward answering the larger question of how external conditions, such as climate change, can affect mutation rates, said UF zoology professor Charles Baer, the paper’s lead author.
Recent studies have suggested that mutation rate may be a function of body size and environmental temperature, based on rates of evolution among species living in different environments, Baer said.
If the baseline mutation rate of an organism is fairly constant, then removing the mutagen from the environment may return the organism’s mutation rate to normal.
www.ufl.edu /mobile/news/articles/wormmutation.htm   (875 words)

A mutation accumulation experiment is conducted by maintaining a set of initially isogenic replicate populations at low effective population size, so that new mutations persist regardless of their fitness effects.
Mutation rates are somewhat different between bacteria and eukaryotes, but among eukaryotes, the rates are not so different between "lower" and "higher" forms.
It was observed that a mutation with a major impact on a phenotypic character generally has two kinds of effects: there is its primary effect, changing the average appearance of the character; but there is also a secondary effect, as the mutant phenotype is also more variable than the wild type.
scienceweek.com /2004/sc040806-5.htm   (1448 words)

 Mutation Rate, Recombination, Multi-gene Reassortment, and Pseudotyping, Report of the Cross-Species Infectivity and ...
RNA viruses have very high mutation rates and many can cause persistent infection in vivo, leading to the accumulation of mutant viruses, some of which might be transmissible to a new host species.
To account for other observations in viruses that cross species barriers, the episodic evolution theory proposes that mutation rates are relatively constant until environmental condition change, resulting in "dramatic shifts in the selection pressure." This would support a mutation pattern with more mutations maintained in active proteins than in silent regions not under direct selection.
Molecular analysis of the MHVH2 variant reveals that mutations in the S and HE attachment and entry glycoproteins are fixed at significantly higher rates as compared with mutation rates measured elsewhere in the viral genome.
www.niaid.nih.gov /dait/cross-species/page5.htm   (1510 words)

 Mutation rate in a gene on the X chromosome holds promise for testing cancer risk
A new study to detect an elevated rate of mutations in a gene on the X chromosome holds promise for developing a test that could identify individuals at risk for developing cancer.
In the study, led by David J. Araten, M.D., Assistant Professor in the Department of Hematology at NYU School of Medicine, the rate of mutations in the gene, called PIG-A, was significantly higher in individuals born with defects in the cellular machinery to repair DNA compared to people without these genetic conditions.
"The mutation rate is widely believed to be a critical factor in the development of cancer, but it has been extremely difficult to study in human cells," says Dr. Araten.
www.eurekalert.org /pub_releases/2005-09/nyum-mri091305.php   (540 words)

 The Effects of Mutation Rate Modulation on GAs Utilizing the Election Operator   (Site not responding. Last check: 2007-11-06)
There an exception to this is possible, though: if the mutation rates cease to matter at any point in the convergence of the strings, selection pressures will mean nothing since the rate strings won't be able to affect the speed of convergence of their buddy populations.
Given that the election operator should afford a greater exploration rate when the dummy strings are more converged, it is to be expected that the optimal mutation rate will be greater for more converged populations.
Since a greater exploration rate pays greater dividents in a situation where the optima are elusive and not necessarily found by inductive methods, it is expected that the more discontinuous fitness function will show a greater average mutation rate.
www.ugcs.caltech.edu /~baldeep/ec101/expected.shtml   (213 words)

 Monkey-Man Hypothesis Thwarted by Mutation Rates
These rates are simply too high for man to have evolved from anything, and if true would show that man must in fact be regressing (a position very consistent with a recent creation of man).
If the deleterious mutation rate is indeed as high as 3 per individual, not only would it thwart the evolutionary scenario of chimp/man common ancestry, it would clearly argue for a recent creation of man. To illustrate this, let's start with a simple model where we will assume heterozygosity
The problem of high mutation rates and its cost on reproduction goes away if comparison between simian and man DNA is not used to determine the mutation rate.
www.evolutionfairytale.com /articles_debates/mutation_rate.htm   (2852 words)

Recessive mutations (most of them are) will not be seen except on the rare occasions that both parents contribute a mutation at the same locus to their child.
The frequency with which a given mutation is seen in a population (e.g., the mutation that causes cystic fibrosis) provides only a rough approximation of mutation rate — the rate at which fresh mutations occur — because of historical factors at work such as
The significance of mutations is profoundly influenced by the distinction between germline and soma.
users.rcn.com /jkimball.ma.ultranet/BiologyPages/M/Mutations.html   (2763 words)

 The Mutation Problem
These problems with mutation rates do not seem to be appreciated by most biologists, and even the creationist sources I have read do not seem to comprehend the seriousness of the problems posed for the theory of evolution by the rates of mutation observed and assumed for evolution.
The general situation is that rates of mutation high enough to account for the ape-human split would lead to the rapid death of the species.
Assuming a mutation per base pair every 200 million years (4.61 per billion years), this means 150 million point mutations in the functional DNA and at least 100 million harmful mutations every 200 million years, since 2/3 of the mutations are harmful.
www.cs.unc.edu /~plaisted/ce/problem.html   (4068 words)

 Estimate of the Mutation Rate per Nucleotide in Humans -- Nachman and Crowell 156 (1): 297 -- Genetics
Estimated mutation rate as a function of ancestral population size.
estimate of the neutral mutation rate and an estimate of the
to the extent that silent mutations are deleterious.
www.genetics.org /cgi/content/full/156/1/297   (4486 words)

 Mitochondrial DNA Mutation Rates
A problem is that rates of mutation are not known by direct measurement, and are often computed based on assumed evolutionary time scales.
It shouldn't be very hard explicitly to measure the rate of mutation of mitochondrial DNA to get a better estimate on this age.
Another discussion of mitochondrial DNA mutation rates and their implications may be found at http://www.rae.org/clocks.html.
www.cs.unc.edu /~plaisted/ce/mitochondria.html   (744 words)

 The antiretrovirus drug 3'-azido-3'-deoxythymidine increases the retrovirus mutation rate.
It was previously observed that the nucleoside analog 5-azacytidine increased the spleen necrosis virus (SNV) mutation rate 13-fold in one cycle of retrovirus replication (V. Pathak and H. Temin, J. Virol.
The strategy of the first assay involved measuring the in vivo rate of inactivation of the lacZ gene in one replication cycle of SNV- and murine leukemia virus-based retroviral vectors.
Proviruses were recovered as plasmids in Escherichia coli, and the rate of inactivation of lacZ alpha was measured.
www.aegis.com /aidsline/1997/aug/M9780621.html   (517 words)

Note that FTDNA considers four markers that have no deduced mutation rates in Panel 3 as “fast moving” and also classifies 459a and 459b as “fast moving”, while Doug deduced the 459a and 459b mutation rates to be slow moving (.0014 each) from Sorenson’s data..
Mutations are from the analysis made by Doug McDonald of Sorenson Molecular Genealogy Foundation’s database, posted at Gen-DNA-L on Feb 28, 2004, with an update to me by email on April 7, 2004.
I understand you to mean that the mutation rate for R1b at 464 is about.016 or.004 for each of the 4 reported alleles.
www.worldfamilies.net /marker.htm   (1225 words)

 The Digital Life Lab at Caltech   (Site not responding. Last check: 2007-11-06)
movie1.5.mpg [7.1Mb]) showing the same pair of organisms at a mutation rate of 1.5, where the flat organism outcompetes the fit one.
The 12 pairs of organisms with replication rate ratio > 1.5.
Parameters a and b for the fitness decay functions, and predicted and measured critical mutation rates.
nemus.dllab.caltech.edu /pubs/nature01   (171 words)

 CSC - Intelligent Design: The Origin of Biological Information and the Higher Taxonomic Categories
Third, DNA mutation rates are far too low to generate the novel genes and proteins necessary to building the Cambrian animals, given the most probable duration of the explosion as determined by fossil studies (Conway Morris 1998b).
Mutations in genes that are expressed late in the development of an organism will not affect the body plan.
Given the extreme improbability of the same structures arising by random mutation and selection in disparate phylogenies, Conway Morris argues that the pervasiveness of convergent structures suggests that evolution may be in some way “channeled” toward similar functional and/or structural endpoints.
www.discovery.org /scripts/viewDB/index.php?command=view&id=2177&progr...   (14205 words)

 Impact of selection, mutation rate and genetic drift on human genetic variation -- Sunyaev et al. 12 (24): 3325 -- ...
mutation rate is similar in the course of the evolution of these
Lercher, M.J. and Hurst, L.D. (2002) Human SNP variability and mutation rate are higher in regions of high recombination.
Li, W.-H. (1993) Unbiased estimation of the rates of synonymous and nonsynonymous substitution.
hmg.oxfordjournals.org /cgi/content/full/12/24/3325   (3803 words)

 Mutation   (Site not responding. Last check: 2007-11-06)
(def) occurs naturally (a normal mistake rate) about one in every million to one in every billion divisions and is probably due to low level natural mutagens normally present in the environment.
Induced mutation (def) is caused by mutagens, substances that cause a much higher rate of mutation.
This is sometimes seen with a single substitution mutation when the change in the DNA base sequence results in a new codon still coding for the same amino acid (see Fig.
www.cat.cc.md.us /biotutorials/protsyn/mutate.html   (983 words)

 Somatic Mutation Rate of the APC Gene -- Iwama 31 (5): 185 -- Japanese Journal of Clinical Oncology
been proposed and their mutation rates were estimated (8,13).
Characteristic of somatic mutation of the adenomatous polyposis coli gene in colorectal tumors.
Correlation between the location of germ-line mutation in the APC gene and the number of colorectal polyps in familial adenomatous polyposis patients.
jjco.oxfordjournals.org /cgi/content/full/31/5/185   (1727 words)

 Between-Host Evolution of Mutation-Rate and Within-Host Evolution of Virulence. (ResearchIndex)   (Site not responding. Last check: 2007-11-06)
Abstract: This paper describes some simulations which study the effect that modifier genes for changes in mutation rate have on suppressing this short-sighted development of virulence, and investigates the interaction between this and a simplified model of immune clearance.
1 Mutation rates as adaptations - Maley - 1997
1 Evolutionarily stable mutation rates in a fluctuating enviro..
citeseer.ist.psu.edu /57869.html   (448 words)

 Evidence for a selectively favourable reduction in the mutation rate of the X chromosome
The most parsimonious explanation is that rodents have a lower mutation rate on the X chromosome than on autosomes.
Furthermore, the rate of synonymous substitution in Y-linked genes is not significantly different from that in autosomal ones.
Li, W.-H. Unbiased estimation of the rates of synonymous and nonsynonymous substitution.
www.nature.com /doifinder/10.1038/386388a0   (762 words)

 MEASUREMENT OF SOMATIC MUTATION RATE IN A TREE   (Site not responding. Last check: 2007-11-06)
The number and size of revertant sectors found on plants homozygous for this mutation will be used to estimate the number of cells in the apical meristem, and the frequency with which descendants of a single cell can come to occupy the entire apical meristem.
The unstable mutation is believed to be in one of two genes encoding enzymes that act late in anthocyanin biosynthesis.
The objectives of this project are to measure the rate of somatic mutation in peach trees, and to estimate the contribution of transposable elements to the overall mutation rate.
www.nal.usda.gov /pgdic/pggrantinfo/1994/9167124.html   (415 words)

 Mutation Rate and Evolution of Fluoroquinolone Resistance in Escherichia coli Isolates from Patients with Urinary Tract ...
Mutation Rate and Evolution of Fluoroquinolone Resistance in Escherichia coli Isolates from Patients with Urinary Tract Infections -- Komp Lindgren et al.
Mutation Rate and Evolution of Fluoroquinolone Resistance in Escherichia coli Isolates from Patients with Urinary Tract Infections
by increasing the rate of accumulation of rare new mutations.
aac.asm.org /cgi/content/abstract/47/10/3222   (676 words)

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