selection pressure

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se·lec·tion pres·sure

impact of effective reproduction due to environmental impact on the phenotype.

selection pressure

Any change in the environment that encourages particular mutations to succeed. For example, antibiotic use kills susceptible bacteria and allows microorganisms with resistant genes to survive and proliferate.

selection pressure

a measure of the amount of relative reproductive disadvantage of one phenotype over another of the same species living together in the same area. Such pressure is usually represented by the selection coefficients which can have a value from zero (no selective disadvantage, maximum FITNESS) to 1.0 (complete selective disadvantage leading to actual death or GENETIC DEATH, minimum fitness).
References in periodicals archive ?
So why should we expect it to be easier to determine the nature of selection pressures that operated several million years ago?
To identify the existence of positive selection pressure at individual codon sites, three likelihood procedures were used as in previous studies (19), (21-22), i.
Both Asian and African cultivated rice "broke" at roughly the same places under selection pressure from early farmers.
The approach undertaken in the present paper will allow signatures of selection to be identified for the unique high intramuscular fat (marbling) of the Hanwoo breed under very intensive artificial selection pressure in the process of breeding programs.
There are selection pressures and other ecological events occurring within and among human hosts that are also important in driving the exchange of resistance genes among gut bacteria," he says.
These feedback loops can be considered to be selection pressures as they can have a determining impact on future possibilities of systems.
Organisms evolve in response to selection pressures in their environment," says Micheal Owen, an extension weed scientist at Iowa State University in Ames.
Lahn denied the accusation and, according to Holden, rejoined that scientists have become "almost like creationists' in their unwillingness to acknowledge that the brain is not exempt from selection pressures.
These programs include a broad base of long-term intellectual property: issued and pending composition of matter patents on potent orally available small molecule inhibitors of a new class of antibiotics with a unique mechanism of action, targeting an underexploited pathway and are not subject to resistance selection pressures caused by the use of existing broad spectrum antibiotics.
At the same time, this aggressive behavior "has a great potential to affect selection pressures since aggression is known to play a role in securing breeding territories.
The method exploits the ability of RNA to evolve in response to selection pressures," Feldheim said.