|
|
|
Genetic drift
A cumulative process involving the chance loss of some genes and the disproportion ate replication of others over successive generations in a small population, so that the frequencies of genes in the population is altered. The process can lead to a population that differs genetically and in appearance from the original population. (source: WCMC) Background from Wikipedia Genetic drift is the term used in population genetics to refer to the statistical drift over time of allele frequencies in a finite population due to random sampling effects in the formation of successive generations. In a narrower sense, genetic drift refers to the expected population dynamics of neutral alleles (those defined as having no positive or negative impact on fitness), which are predicted to eventually become fixed at zero or 100% frequency in the absence of other mechanisms affecting allele distributions. Whereas natural selection describes the tendency of beneficial alleles to become more common over time (and detrimental ones less common), genetic drift refers to the fundamental tendency of any allele to vary randomly in frequency over time due to statistical variation alone, so long as it does not comprise all or none of the distribution. Genetic drift may be modeled as a stochastic process that arises from the role of random sampling in the production of offspring. The genes of each new generation are not a simple copy of the genes of the successful members of the previous one, but rather a sampling, which includes some statistical error. Drift is the cumulative effect over time of this sampling error on the allele frequencies in the population. By definition, genetic drift has no preferred direction. A neutral allele may be expected to increase or decrease in any given generation with equal probability. Given sufficiently long time, however, the mathematics of genetic drift (cf. random walk) predict the allele will either die out or be present in 100% of the population, after which time there is no random variation in the associated gene. In this regard, genetic drift tends to sweep gene variants out of a population over time, such that all members of a species would eventually be homozygous for this gene. Genetic drift is opposed in this regard by genetic mutation which introduces novel variants into the population according to its own random processes. Like selection, genetic drift acts on populations, altering the frequency of alleles (gene variations) and the predominance of traits. Drift is observed most strongly in small populations and results in changes that need not be adaptive. Science Daily (press release)...full article Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a The genetic map maker - Oct 17, 2007 Nature.com (subscription),I was able to show that random genetic drift, then the Cinderella of evolution, could explain a great fraction of genetic variation, whereas — at least with EVOLUTION, NATURAL SELECTION, NEUTRAL THEORY, GENETIC DRIFT - Oct 3, 2007 Newswise (press release)Newswise — “Survival of the fittest� has popularly described evolution for more than a century, but a new study published in the Royal Society journal Full Text - Oct 18, 2007 Science Magazine (subscription)Such serendipity is called genetic drift, and it contrasts with the idea that fitness in a particular environment--natural selection--not chance, Timothy Ryan Sides with the Dinosaurs - Oct 15, 2007 the newspaper,...undeniable evidence of the mechanisms -like mutation, natural selection, and genetic drift- which goes a long way towards explaining how life evolved. Full Text - Oct 11, 2007 Science Magazine (subscription)In this conclusion, Price is supported by theoretical and experimental studies, which indicate that genetic drift is less efficient than selection in the Price synthesizes bird speciation studies, examining nearly 10000 ... - Oct 18, 2007 University of Chicago Chronicle...of sexual selection and natural selection in bird speciation, and the roles of geographical isolation, ecological differentiation and genetic drift. On DNA and race - Oct 7, 2007 seattlepi.com BuzzworthyThis process, known as genetic drift, caused markers to evolve at different frequencies in different populations and gave rise to the ethnic diversity we Evolution is a theory - Sep 23, 2007 Northwest Herald,It includes components such as mutation, natural selection, genetic drift, gene duplication, and many more. Many use the word 'theory' in the vernacular Birds' memories help them learn to fly - Aug 15, 2007 Science Daily (press release)...full article Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a Chance and isolation gave humans elegant skulls - Jul 24, 2007 New Scientist (subscription),A statistical analysis suggests that the skull differences between the two species stems not from positive natural selection but from genetic drift, Mapping the origins of the lab mouse - Aug 15, 2007 Ars Technica,...experiments to be performed on large groups, or at different times, with relative certainty that genetic drift isn't going to be much of an influence. Black Death casts a genetic shadow over England - Aug 1, 2007 New Scientist (subscription),Hoelzel thinks random genetic drift may have lowered genetic diversity naturally. But the large unexpected drop in diversity was more likely to have been Handsome By Chance: Why Humans Look Different From Neanderthals - Aug 13, 2007 Science Daily (press release)Instead, random "genetic drift" is the likeliest reason for these skull differences. Weaver conducted the research with Charles Roseman, an anthropologist Genetically modified corn ains approval - Jul 27, 2007 Central Maine Morning Sentinel,Genetic drift, the cross pollination of a genetically modified crop with a non-modified crop, may occur, said Jemison, a water quality and soil specialist » Report: Not all evolution has purpose « - Jul 24, 2007 Baltimore Examiner,Describing their contributions to genetic drift online in Public Library of Science Genetics, Katsanis says the Johns Hopkins experiments demonstrated that MicroRNA: Introducing the mirtron - Jul 30, 2007 Nature.com (subscription),If so, mirtrons would be lost rapidly through selection if they were deleterious, or slowly through genetic drift if they were neutral, Full Text - Aug 9, 2007 Science Magazine (subscription)In this work, we used populations with an intermediate effective population size—big enough that genetic drift is unlikely to drive slightly deleterious GENETICALLY MODIFIED CORN Next step: Do no harm - Aug 1, 2007 Kennebec Journal,Equally worrisome was the issue of so-called "genetic drift" -- unlike the earlier experiment with Bt potatoes, which self-pollinate, one corn plant Handsome by Chance - Aug 1, 2007 UC Davis,Instead, random "genetic drift" is the likeliest reason that humans acquired smooth foreheads and strong lower jaws. Weaver conducted the research with Chance, not natural selection, gave Homo sapiens their elegant skulls - Jul 25, 2007 DailyIndia.com,...revealed that the genetic drift, in which physical features change randomly, without an environmental driving force, was responsible for the skull Scientists prove we are just like sheep - Mar 27, 2007 The Gateway,So don’t let the scientists try to pull the wool over your eyes with fancy statistics about “genetic drift� and the “Founder Effect�: after all, Incestuous sheep surprise scientists - Mar 27, 2007 The Gateway,The problem with earlier assumptions about evolution, said Coltman, is that they often only include genetic drift and the Founder Effect. Climate change said to affect evolution - Mar 16, 2007 Science Daily (press release)Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a population due Wabash Valley students reap top honors in Regional Science Fair - Mar 20, 2007 Terre Haute Tribune Star,TERRE HAUTE — An animal sciences project that examines the genetic drift within white-tailed deer and a project that examines how energy can be created from The State of the Salmon - Mar 20, 2007 YubaNet,The term for this is "genetic drift," and it is essentially creating a new species of salmon. "We have produced a poor quality and defective fish," Swanson This statement is not a tautology - Apr 4, 2007 ScienceBlogsNatural selection is one possible cause, but so are random genetic drift, mutation and migration. Incidentally, it is a curiosity of some creationist Full Text - Mar 22, 2007 Science Magazine (subscription)Alternatively, mitonuclear transfer could be a neutral process, guided by random genetic drift, or an adaptive process, guided by genes with additive Geriatrics required: bomb disposal, asbestos removal etc - Mar 14, 2007 Times Online,...“What is amazing is that models of genetic drift predict the genetic diversity of these animals should have been lost over time, but we’ve found that it has Education Briefly - Mar 27, 2007 Terre Haute Tribune Star,Sperry placed second in the regional competition and received a $1500 college scholarship for research titled “Immunological Correlates of Genetic Drift Geriatrics required: bomb disposal, asbestos removal etc - 15 Mar 2007 Times Online,...“What is amazing is that models of genetic drift predict the genetic diversity of these animals should have been lost over time, but we’ve found that it has Remote sheep population resists genetic drift - Mar 9, 2007 Biology News Net (press release),This finding challenges the widely accepted theory of genetic drift, which states the genetic diversity of an inbred population will decrease over time. Genetic Drift also 'strays from the herd' - Mar 8, 2007 The Grand Rapids Press,Official since New Year's Eve in December 2004, Genetic Drift includes second lead/rhythm guitarist Greg Russo, drummer Marco Edwards and bassist Mike Remote sheep teach genetics - Mar 9, 2007 Science Daily (press release)Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a population due Remote Sheep Teach Genetics - Mar 9, 2007 Post ChronicleThe widely-accepted theory of "genetic drift" would dictate the animals' genetic diversity, or the amount of possible gene combinations a mating pair can Untangling nature of 'regressive evolution' in cavefish - Feb 15, 2007 HULIQ,..."Regressive evolution," or the reduction of traits over time, is the result of either natural selection or genetic drift, according to a study on cavefish Do Humans have a Political Gene? - Mar 3, 2007 Al-Jazeerah.info,...campaigns designed to polarize the political factions of our society specifically, but also could be caused by a genetic drift to lower intelligence. Full Text - Mar 1, 2007 Science Magazine (subscription)...a dual-topology protein could evolve via genetic drift toward a K+R bias, whereby the subunits obtain a fixed orientation (see the figure). The weekend in West Michigan - Mar 8, 2007 The Grand Rapids Press,Genetic Drift with If He Dies He Dies, Sin Theorem, the Trial, Azriel, 9 pm Saturday, The Rocker, inside AMF Miracle Lanes, 3700 Plainfield Ave. Freaky New Bats Found by DNA Barcoding - Feb 18, 2007 LiveScience.com,...“These unique barcodes rise through the process of evolution, through genetic drift and through selection.� The scientists propose using a stretch of 648 Addo elephants put rare plants at risk - Feb 27, 2007 The Herald Eastern Cape,In a world first, Addo introduced elephants from the Kruger National Park to address the problem of in-breeding and “genetic drift� which had left females After dark - Feb 22, 2007 The Grand Rapids Press,SW, 451-8232, sectionlive.com -- WKLQ's Heavyweight Championship of Rock finals, with Flesh For The Beast, Shackle Jack, Genetic Drift, UnAltered, Full Text - Mar 1, 2007 Science Magazine (subscription)It seems unlikely that genetic drift or bottlenecks can explain the results, given the size of the total viral population. Moth population sizes were Parental gene competition theory debated - Nov 29, 2006 Science Daily (press release)Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a population due Enforce the Precautionary principle: genetically engineering foods ... - Dec 6, 2006 PEJ News,Also with genetic drift it is possible that all a wide range of organic crops could be contaminated with genetically engineered produce. When Two Mutants Collide: How Genetic Disorders Can Be Partially ... - Oct 4, 2006 Science Daily (press release)Genetic drift -- Genetic drift is the term used in population genetics to refer to the statistical drift over time of gene frequencies in a population due to ... When Genes Evolve, a Staccato Rhythm - Oct 5, 2006 Science Now,Pagel attributes the bursts of genetic change not just to natural selection, but also to an additional phenomenon called genetic drift, in which some genetic ... 'Texas Chainsaw' prequel a hack job - Oct 7, 2006 Jam! Showbiz,BOTTOM LINE: The prequel to the 2003 remake (how's that for genetic drift?), this comes as close to an R rating as it can, as far as butchering, evisceration ... Genetic evidence for punctuated equilibrium - Oct 6, 2006 Scientist,Speciation often takes place when a population of organisms is isolated, which means that genetic drift in a small population or fast adaptation to a new niche ... Farmers debate biotechnology use in ag industry - Sep 29, 2006 The Prairie Star,He said there is also no way to control “genetic drift,� what happens when the genes from GE plants get into the environment and contaminate it. ... Dozens of new species found in underwater wonderland - Sep 17, 2006 Independent,...like area in the north of the region - had been closed by geological movements, which allowed new species to develop through natural selection and genetic drift ... News index | RSS | News Feed Advertisements: Organic Apparel from Patagonia | Insect-repelling clothing |
MONGABAY.COM
T-SHIRTS 
CALENDARS 
CANVAS BAGS 
|
