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Genetic variation can be identified at many levels. Identifying genetic variation is possible from observations of phenotypic variation in either quantitative traits (traits that vary continuously and are coded for by many genes, e.g., leg length in dogs) or discrete traits (traits that fall into discrete categories and are coded for by one or a few genes, e.g., white, pink, or red petal color ...
Genetic variability is either the presence of, or the generation of, genetic differences. It is defined as "the formation of individuals differing in genotype, or the presence of genotypically different individuals, in contrast to environmentally induced differences which, as a rule, cause only temporary, nonheritable changes of the phenotype."
Human genetic variation is the genetic ... cause of genetic variation is due to the ... most populations have continuous gene flow with other neighboring populations ...
Irregular variation within a historical experience base; and; Lack of significance in individual high or low values. The outcomes of a perfectly balanced roulette wheel are a good example of common-cause variation. Common-cause variation is the noise within the system. Walter A. Shewhart originally used the term chance cause. [1]
In an early summary of the theory of evolution of continuous variation, Sewall Wright, a graduate student who trained under Castle, summarized contemporary thinking about the genetic basis of quantitative natural variation: "As genetic studies continued, ever smaller differences were found to mendelize, and any character, sufficiently ...
This introduces the topic of gradualism, which is a slow but continuous accumulation of changes over long periods of time. [34] This is largely because the results of disruptive selection are less stable than the results of directional selection (directional selection favors individuals at only one end of the spectrum).
Human variability, or human variation, is the range of possible values for any characteristic, physical or mental, of human beings. Frequently debated areas of variability include cognitive ability , personality , physical appearance ( body shape , skin color , etc.) and immunology .
Selection causes adaptation to the local environment, resulting in different genotypes or phenotypes being favoured in different environments. This diversifying force is countered by gene flow, which has a homogenising effect on populations and prevents speciation through causing genetic admixture and blurring any distinct genetic boundaries.