Evolution
... of any species, in such a way as to result in new
selective forces.
Genetic drift
Genetic drift ... in allele frequency that cannot be ascribed to
selective pressures, but are due instead to events that are ... altering the allele frequency outside of "normal"
selective pressures.
Many aspects of genetic drift depend ...
Molecular evolution
... in gene frequency that cannot be ascribed to
selective pressures, but are due instead to events that are ... , meaning mutations that do not convey a
selective advantage or disadvantage to the individual that ... locus. Beyond this number of alleles, the
selective advantage of presence of those alleles in ...
Pigment
... in plant or animal cells which is the result of
selective absorption. Some biological material has so-called structural color, which is the result of
selective reflection or iridescence , usually done with ... .
Because pigment color is the result of
selective absorption, there is no such thing as white ...
Apoptosis
... - specifically on chick neural tube development - has suggested how
selective cell proliferation, combined with
selective apoptosis, sculpts developing tissues in vertebrates. During vertebrate ...
Eugenics
... of eugenics
8.2 Pro-eugenics websites
Galton's theory
selective breeding was suggested as early as the time of Plato , who believed that ... based on the Mendelian laws.
Eugenics developed to refer to human
selective reproduction with the intent to create children with desirable traits, ...
Selective serotonin reuptake inhibitor
...
selective serotonin reuptake inhibitors ( SSRIs ) are a class of antidepressants . ... of L-Tryptophan
References
Tamam, L. and Ozpoyraz, N. (2002).
selective serotonin reuptake inhibitor discontinuation syndrome: a review. Advances ...
Antibiotic resistance
... third generation cephalosporins , greatly hastens the development of methicillin resistance, even in organisms that have never been exposed to the
selective pressure of methicillin per se . Other factors contributing towards resistance include incorrect diagnosis, unnecessary prescriptions, improper use ...
Biological membrane
... the size, charge and other chemical properties of the atoms and molecules attempting to cross it will determine whether they succeed to do so.
selective permeability is essential for effective separation of a cell or organelle from its surroundings.
If a particle is too large or otherwise unable to ...
Biotechnology
... rare.
Biotechnology timeline
8000BC Collecting of seeds for replanting. Evidence that Babylonians , Egyptians and Romans used
selective breeding ( artificial selection ) practices to improve livestock .
6000BC Brewing beer , fermenting wine , baking bread with help of ...
Cancer
... or vitamin E or both experience a reduced incidence of prostate cancer in comparison to men taking placebo pills.
Daily use of tamoxifen , a
selective estrogen receptor modulator, for up to 5 years, has been demonstrated to reduce the risk of developing breast cancer in high-risk women by about ...
Cell growth
... process of meiosis? You may think you know why you have sex , but you probably do not know the real reason; the reason why meiosis confers a
selective advantage . Notice that when meiosis starts, the two copies of chromosome number 2 are adjacent to each other. During this time, there can be ...
Chromatography
... determining polymer molecular weight distribution, but is low resolution .
Affinity chromatography
Affinity chromatography is based on
selective non-covalent interaction between an analyte and specific molecules. It is very specific, but not very robust . It is often used in biochemistry in ...
Genetic code
... look at the table shows patterns that suggest that this is not the case.
Recent aptamer experiments have shown that amino acids have indeed a
selective chemical affinity for the base triplets that code for them. This suggests that the current, complex transcription mechanism involving tRNA and ...
Experimental evolution
... human history
Unwittingly, humans have carried out evolution experiments for as long as they have been domesticating plants and animals.
selective breeding of plants and animals has led to varieties that differ dramatically from their original wild-type ancestors. Examples are the cabbage ...
Genetic drift
... (depending on whether the allele is beneficial or harmful). However, if the population is very small, drift will predominate. In this case, weak
selective effects may not be seen at all as the small changes in frequency they would produce are overshadowed by drift.
Genetic drift in populations
...
Genetic code
... look at the table shows patterns that suggest that this is not the case.
Recent aptamer experiments have shown that amino acids have indeed a
selective chemical affinity for the base triplets that code for them. This suggests that the current, complex transcription mechanism involving tRNA and ...
Genomics
... , that sequence is said to have been conserved among the species. Evolutionary conservation of a DNA sequence may imply that it confers a relative
selective advantage to the organisms that possess it. Conservation also suggests that sequence has functional significance. It may be a protein coding ...
Hyperpolarization
... , hyperpolarization occurs when a cell's membrane potential dips below its resting level .
In physics , hyperpolarization is the
selective polarization of nuclear spin in atoms far beyond normal thermal equilibrium.
...
Modern evolutionary synthesis
... gene is the only true unit of selection . Dawkins further extended the Darwinian idea to include non-biological systems exhibiting the same type of
selective behavior of the 'fittest' such as memes in culture.
See also: Population genetics
References
Dobzhansky, T. Genetics and the Origin ...
Antibiotic resistance
... third generation cephalosporins , greatly hastens the development of methicillin resistance, even in organisms that have never been exposed to the
selective pressure of methicillin per se . Other factors contributing towards resistance include incorrect diagnosis, unnecessary prescriptions, improper use ...
Magnetic resonance imaging
... moved into that plane.
Magnetic resonance spectroscopy
Magnetic resonance spectroscopy (MRS), also known as MRSI (MRS Imaging) and Volume
selective NMR Spectroscopy, is a technique which combines the spatially-addressable nature of MRI with the spectroscopically-rich information obtainable from ...
Natural selection
... will disappear as the offspring who carry them are replaced by their more successful relatives.
Therefore, certain traits are preserved due to the
selective advantage they provide to their holders, allowing the individual to leave more offspring than individuals without the trait(s). Eventually, through ...
Plasmid
...
4 Applications of plasmids
5 See also
Antibiotic resistance
Plasmid often contain genes or gene-cassettes that confer a
selective advantage to the bacterium harboring them, e.g., the ability to build an antibiotic resistance . Every plasmid contains at least one DNA sequence ...
Punctuated equilibrium
... of the population through which they must ... [in] small, peripherally isolated groups [that] are cut off from their parental stock ...
selective pressures are usually intense because peripheries mark the edge of ecological tolerance for ancestral forms. Favorable variations spread ... ...
Red Queen
... their short lifespans. As they evolve, they attack their hosts in a variety of ways. Two consecutive generations might be faced with very different
selective pressures. If this change is rapid enough, it might explain the persistence of sex.
References
Matt Ridley ( 1995 ) The Red Queen: Sex ...
Speciation
... or migration). The isolated populations are then liable to diverge evolutionarily over many generations as a) they become subjected to dissimilar
selective pressures and b) they independently undergo genetic drift ; particularly when one of the subpopulations is small (a scenario that leads to the " ...
Synapse
... number and replenishment rate of vesicles also are subject to regulation, as are many other elements of synaptic transmission. The drugs known as
selective serotonin re-uptake inhibitors or SSRIs affect certain synapses by inhibiting the re-uptake of the neurotransmitter serotonin .
One important ...