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 ?
In the sparse populations of Barn Swallows seen in Japan, in contrast with the colonial populations seen in Europe, selection pressure favoring the occupation of well-constructed nests is high to avoid high nest predation by crows (Hasegawa et al.
Estimation of selection pressure on coding sequences: The nucleotide sequences of Dicer coding sequences of divergent species were subjected to codon based tests, in order to determine the effect of evolutionary forces that have tailored its encoded products.
Environmental factors and production practices influence species composition at any location, a phenomenon known as selection pressure.
According to experts, selection pressure has made almost all disease causing bacteria resistant to antibiotics commonly used to treat them.
It is likely that ISD-susceptible avian species evolved while on foods that were very low in bioavailable iron, so there was strong selection pressure for the efficient capture of the small amount of dietary iron but low selection pressure for preventing iron toxicities.
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.
Such a two-track research program, with strong selection pressure, may not advance the authors' aims of keeping legitimate public control over key information about capabilities and risks and generating attendant public trust in decisions about whether, when, and how to develop or deploy CE capabilities.
The place that organisms occupy on this sliding scale of forces depends in part on the extent to which Darwin's natural selection pressure is able to counter or enhance these intrinsic biases.
Mere imitation learning would then have increased the likelihood that an innovation in one generation would reappear in the next, and as this cultural innovation became widespread and perhaps even integral to the hominin lifestyle, it would have introduced a new selection pressure into the mix.
jejuni would probably decrease in the absence of antimicrobial drug selection pressure (11).
Nineteen-year-old winger Ben Blackmore has moved to the John Smith's Stadium on a one-year contract, with the initial aim of putting selection pressure on the club's experienced outside backs.
This information suggests that genes encoding those proteins come under intense selection pressure by the immune system during the initial acute infection.