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At present the best-understood examples of polygenic adaptation are in humans, and particularly for height, a trait that can be interpreted using data from genome-wide association studies. In a 2012 paper, Joel Hirschhorn and colleagues showed that there was a consistent tendency for the "tall" alleles at genome-wide significant loci to be at ...
Human height is a continuous trait meaning that there is a wide range of heights. There are an estimated 50 genes that affect the height of a human. Environmental factors, like nutrition, also play a role in a human's height. Other examples of complex traits include: crop yield, plant color, and many diseases including diabetes and Parkinson's ...
A polygene is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait, thus contributing to multiple-gene inheritance (polygenic inheritance, multigenic inheritance, quantitative inheritance [1]), a type of non-Mendelian inheritance, as opposed to single-gene inheritance, which is the core notion of Mendelian inheritance.
Unlike monogenic traits, polygenic traits do not follow patterns of Mendelian inheritance (discrete categories). Instead, their phenotypes typically vary along a continuous gradient depicted by a bell curve. [8] An example of a polygenic trait is human skin color variation.
The infinitesimal model, also known as the polygenic model, is a widely used statistical model in quantitative genetics and in genome-wide association studies.Originally developed in 1918 by Ronald Fisher, it is based on the idea that variation in a quantitative trait is influenced by an infinitely large number of genes, each of which makes an infinitely small (infinitesimal) contribution to ...
In biology, polymorphism [1] is the occurrence of two or more clearly different morphs or forms, also referred to as alternative phenotypes, in the population of a species. To be classified as such, morphs must occupy the same habitat at the same time and belong to a panmictic population (one with random mating).
Complex traits in particular are more likely to have a polygenic basis. [18] Advances in genetic technology have allowed scientists to more closely investigate the genetic basis of complex traits, leading to an accumulation of evidence supporting the importance of polygenic control in understanding the evolution of these traits.
For example, crocodiles possess a temperature-dependent sex determining polyphenism, where sex is the trait influenced by variations in nest temperature. [ 3 ] When polyphenic forms exist at the same time in the same panmictic (interbreeding) population they can be compared to genetic polymorphism . [ 4 ]