Epistasis: Difference between revisions

From The School of Biomedical Sciences Wiki
Jump to navigation Jump to search
No edit summary
No edit summary
Line 1: Line 1:
Epistasis is&nbsp;an interaction in which the [[Genotype|genotype]] at&nbsp;once locus&nbsp;will mask/suppress the&nbsp;[[Phenotypic expression|phenotypic expression]] of the [[Genotype|genotype]] at&nbsp;another [[Locus|locus]].<ref>Daniel L. Hartl, Maryellen Ruvolo, (2012) Genetic:s analysis of genes and genomes, 8th edition, Burlington, Massachusetts: Jones &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Bartlett Learning</ref>  
Epistasis is&nbsp;an interaction in which the [[Genotype|genotype]] at&nbsp;once locus&nbsp;will mask/suppress the&nbsp;[[Phenotypic expression|phenotypic expression]] of the [[Genotype|genotype]] at&nbsp;another [[Locus|locus]].<ref>Daniel L. Hartl, Maryellen Ruvolo, (2012) Genetic:s analysis of genes and genomes, 8th edition, Burlington, Massachusetts: Jones &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Bartlett Learning</ref>  


An example of epistasis occurs in Labrador Retriever coat colour. Coat colour of Labrador Retreivers is determined by two genes: the B gene and the E gene and the [https://teaching.ncl.ac.uk/bms/wiki/index.php/Phenotype phenotypes] can be either black coats, chocolate brown coats or yellow coats. A [https://teaching.ncl.ac.uk/bms/wiki/index.php/Dominant dominant] B and a dominant E gene present in the genoytype (e.g. BBEE, BBEe, BbEE, BbEe)&nbsp;will give a Labrador with a black coat, a dominant E gene present with[https://teaching.ncl.ac.uk/bms/wiki/index.php/Recessive_gene recessive ]B genes (e.g. bbEe, bbEE) will give Labradors with a chocolate brown coats. However, the [https://teaching.ncl.ac.uk/bms/wiki/index.php/Genotype genotype] of recessive E (e) is recessive but also epistatic in [https://teaching.ncl.ac.uk/bms/wiki/index.php/Homozygous homozygous] form (ee) so if the genotype 'ee' is present the Labrador will have a yellow coat, regardless of the B gene genotype. This is an example of epistasis as the genotype at the E gene determines the expression of the B gene<ref>https://teaching.ncl.ac.uk/bms/wiki/index.php/Phenotype</ref>.  
An example of epistasis occurs in Labrador Retriever coat colour. Coat colour of Labrador Retreivers is determined by two genes: the B gene and the E gene and the [https://teaching.ncl.ac.uk/bms/wiki/index.php/Phenotype phenotypes] can be either black coats, chocolate brown coats or yellow coats. A [https://teaching.ncl.ac.uk/bms/wiki/index.php/Dominant dominant] B and a dominant E gene present in the genoytype (e.g. BBEE, BBEe, BbEE, BbEe)&nbsp;will give a Labrador with a black coat, a dominant E gene present with[https://teaching.ncl.ac.uk/bms/wiki/index.php/Recessive_gene recessive ]B genes (e.g. bbEe, bbEE) will give Labradors with a chocolate brown coats. However, the [https://teaching.ncl.ac.uk/bms/wiki/index.php/Genotype genotype] of recessive E (e) is recessive but also epistatic in [https://teaching.ncl.ac.uk/bms/wiki/index.php/Homozygous homozygous] form (ee) so if the genotype 'ee' is present the Labrador will have a yellow coat, regardless of the B gene genotype. This is an example of epistasis as the genotype at the E gene determines the expression of the B gene<ref>https://online.science.psu.edu/biol011_sandbox_7239/node/7371</ref>.  


<span style="background-color: initial; font-size: 17.5296px; font-weight: bold;">Refereneces</span>  
<span style="background-color: initial; font-size: 17.5296px; font-weight: bold;">Refereneces</span>  

Revision as of 12:36, 4 December 2016

Epistasis is an interaction in which the genotype at once locus will mask/suppress the phenotypic expression of the genotype at another locus.[1]

An example of epistasis occurs in Labrador Retriever coat colour. Coat colour of Labrador Retreivers is determined by two genes: the B gene and the E gene and the phenotypes can be either black coats, chocolate brown coats or yellow coats. A dominant B and a dominant E gene present in the genoytype (e.g. BBEE, BBEe, BbEE, BbEe) will give a Labrador with a black coat, a dominant E gene present withrecessive B genes (e.g. bbEe, bbEE) will give Labradors with a chocolate brown coats. However, the genotype of recessive E (e) is recessive but also epistatic in homozygous form (ee) so if the genotype 'ee' is present the Labrador will have a yellow coat, regardless of the B gene genotype. This is an example of epistasis as the genotype at the E gene determines the expression of the B gene[2].

Refereneces

  1. Daniel L. Hartl, Maryellen Ruvolo, (2012) Genetic:s analysis of genes and genomes, 8th edition, Burlington, Massachusetts: Jones &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; Bartlett Learning
  2. https://online.science.psu.edu/biol011_sandbox_7239/node/7371