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A 2008 analysis of test scores across 41 countries published in Science concluded that "data shows a higher variance in boys' than girls' results on mathematics and reading tests in most OECD countries", the results implying that "gender differences in the variance of test scores are an international phenomenon". However, it also found that ...
Environmental variance can be explicitly modeled by studying individuals across a broad range of environments, although inference of genetic variance from phenotypic and environmental variance may lead to underestimation of heritability due to the challenge of capturing the full range of environmental influence affecting a trait.
Genetic variation is the difference in DNA among individuals [1] or the differences between populations among the same species. [2] The multiple sources of genetic variation include mutation and genetic recombination. [3] Mutations are the ultimate sources of genetic variation, but other mechanisms, such as genetic drift, contribute to it, as ...
A graphical representation of the typical human karyotype The human mitochondrial DNA. Human genetic variation is the genetic differences in and among populations.There may be multiple variants of any given gene in the human population (), a situation called polymorphism.
Genetic variation in humans may mean any variance in phenotype which results from heritable allele expression, mutations, and epigenetic changes. While human phenotypes may seem diverse, individuals actually differ by only 1 in every 1,000 base pairs and is primarily the result of inherited genetic differences. [ 8 ]
The word "allele" is a short form of "allelomorph" ("other form", a word coined by British geneticists William Bateson and Edith Rebecca Saunders) in the 1900s, [7] [8] which was used in the early days of genetics to describe variant forms of a gene detected in different phenotypes and identified to cause the differences between them.
Heritability is the proportion of variance caused by genetic factors of a specific trait in a population. [1] Falconer's formula is a mathematical formula that is used in twin studies to estimate the relative contribution of genetic vs. environmental factors to variation in a particular trait (that is, the heritability of the trait) based on ...
Structural variation is an important type of human genetic variation that contributes to phenotypic diversity. [2] There are microscopic and submicroscopic structural variants which include deletions, duplications, and large copy number variants as well as insertions, inversions, and translocations. [1]