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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.
A study published in 2006 used phylogeny to compare the genetic architecture of differing human skin color. In this study, researchers were able to suggest a speculative framework for the evolutionary history underlying current-day phenotypic variation in human skin pigmentation based on the similarities and differences they found in the ...
A phenotypic trait is an obvious, observable, and measurable characteristic of an organism; it is the expression of genes in an observable way. An example of a phenotypic trait is a specific hair color or eye color. Underlying genes, that make up the genotype, determine the hair color, but the hair color observed is the phenotype.
Similar genotypic changes may result in similar phenotypic alterations, even across a wide range of species. [1] The genotype–phenotype distinction is drawn in genetics. The "genotype" is an organism's full hereditary information. The "phenotype" is an organism's actual observed properties, such as morphology, development, or behavior.
Polygenic inheritance refers to inheritance of a phenotypic characteristic (trait) that is attributable to two or more genes and can be measured quantitatively. Multifactorial inheritance refers to polygenic inheritance that also includes interactions with the environment.
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 ...
However, if the phenotypic optimum changes, then the population can adapt by small directional shifts in allele frequencies spread across all the variants that affect the trait. Polygenic adaptation can occur relatively quickly (as described in the breeder's equation ), however it is difficult to detect from genomic data because the changes in ...
A polygenic trait is one whose phenotype is dependent on the additive effects of multiple genes. The contributions of each of these genes are typically small and add up to a final phenotype with a large amount of variation. A well studied example of this is the number of sensory bristles on a fly. [23]