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    Anyone want to have ago at explaining the damn thing, I know its interaction between different gene loci to mask/supress the expression of each other but whats all this about antagonistic and complimentary action?
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    (Original post by clad in armour)
    Anyone want to have ago at explaining the damn thing, I know its interaction between different gene loci to mask/supress the expression of each other but whats all this about antagonistic and complimentary action?
    Epistasis is a type of gene interaction.In this interaction quite often more than one gene happens to share same metabolic pathway.In other words: A gene interaction in which a characteristic's expression is controlled by two or more genes.
    We end up with Hypostatic and epistatic genes:
    Epistatic gene is the one which suppresses other gene's phenotype while hypostatic is a gene which has it's phenotype suppressed by an epistatic gene.
    Epistatic reduces the no. of phenotype unlike your classic 9 : 3: 3 : 1 ratio.
    A dominant epistasis gives a ratio of: 12 : 3: 1 while a recessive epistasis 9 : 4: 3

    Take mice coat colour as an example:
    Gene A basically codes for the distribution of melanin while gene C codes for the making of melanin.We know that black coat is recessive "aa" while agouti color is AA or Aa.A genotype CC or CC codes for the melanin while a recessice homozygote would result in no melanin being produced at all (albino) hence Gene A doesn't make any cameo appearance.So we get epistatic gene being:C and hypostatic:A
    Hope I made any sense

    Some worthy defintions: Hypostatic: A gene which has it's phenotype inhibited by another gene.
    Epistatic: A gene which inhibits the expression of another gene.
    EDIT: By the way I assume you are sitting f215 this jan? if so check this thread out xD :
    http://www.thestudentroom.co.uk/show....php?t=1495727
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    So mind if i ask what is the difference between recessive and dominant epistasis?
 
 
 
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