World Library  
Flag as Inappropriate
Email this Article

Polygene

Article Id: WHEBN0001969807
Reproduction Date:

Title: Polygene  
Author: World Heritage Encyclopedia
Language: English
Subject: Genetic architecture, Eye color, Quantitative trait locus, Allele, Feather pecking
Collection: Genetics, Inheritance
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Polygene

A polygene, multiple factor, multiple gene inheritance, or quantitative gene is a group of non-epistatic genes that together influence a phenotypic trait. The precise loci or identities of the non-allelic genes are often unknown to biologists. Advances in statistical methodology and high throughout sequencing are, however, allowing researchers to locate candidate genes for the trait. These genes are generally pleiotropic as well. The genes that contribute to type 2 diabetes are thought to be mostly polygenes.[1]

Traits with polygenic determinism correspond to the classical quantitative characters, as opposed to the qualitative characters with monogenic or oligogenic determinism.

Contents

  • Inheritance 1
  • Trait distribution 2
  • Mapping polygenes 3
  • References 4

Inheritance

Polygenic inheritance occurs when one characteristic is controlled by two or more Drosophila, for instance, display polygeny with traits such as wing morphology,[3] bristle count[4] and many others.

Trait distribution

The frequency of the phenotypes of these traits generally follows a normal continuous variation distribution pattern. This results from the many possible allelic combinations. When the values are plotted, a bell-shaped curve is obtained. The mode of the distribution represents the optimal, or fittest, phenotype. The more genes are involved, the smoother the estimated curve. However, in this model all genes must code for alleles with additive effects. This assumption is often unrealistic as many genes display epistasis effects which can have unpredictable effects on the distribution of outcomes, especially when looking at the distribution on a fine scale.[5]

Mapping polygenes

Example of a genome-wide scan for QTL of osteoporosis

Traditionally, mapping polygenes requires statistical tools available to help measure the effects of polygenes as well as narrow in on single genes. One of these tools is

  1. ^ Emerging epidemic of type 2 diabetes in youth
  2. ^ Falconer, D. S. & Mackay TFC (1996). Introduction to Quantitative Genetics. Fourth edition. Addison Wesley Longman, Harlow, Essex, UK.
  3. ^ Quantitative Trait Loci Affecting Components of Wing Shape in Drosophila melanogaster
  4. ^ http://service004.hpc.ncsu.edu/mackay/Good_Mackay_site/PUB_files/Mackay%202005%20Trends%20Genet.pdf
  5. ^ Ricki Lewis (2003), Multifactorial Traits, McGraw-Hill Higher Education 
  6. ^ Consoli L, Lefèvre A, Zivy M, de Vienne D, Damerval C (Apr 2002). "QTL analysis of proteome and transcriptome variations for dissecting the genetic architecture of complex traits in maize.". Plant Mol Biol. 48 (5-6): 575–581.  

References

Another interest of statistical geneticists using QTL mapping is to determine the complexity of the genetic architecture underlying a phenotypic trait. For example, they may be interested in knowing whether a phenotype is shaped by many independent loci, or by a few loci, and do those loci interact. This can provide information on how the phenotype may be evolving.

[6]

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.