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Dominant and recessive epistasis Watch

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    My teacher gave me a question to work through and I incurred some confusion that she wasn't able to fully clarify.

    The question gave a gene with two alleles, A and a, which determine the colour of the coat in mice.

    AA or Aa is Albino fur and aa is black fur.

    We are then told that these colours can only be expressed in the presence of at least one dominant allele of the gene C/c. Otherwise, the fur will be Agouti in the case of cc.

    Crossing aaCC with AAcc gives an F1 generation of AaCc.

    However, for the F2 generation (crossing AaCc with AaCc), the phenotypic ratio is 9:3:4.

    This is what has confused me, because this ratio occurs in recessive epistasis. But is this not dominant epistasis?

    Thanks!
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    My friend messaged me with a similar question just the other day...

    When you initially crossed aaCC and AAcc, did you use the combinations AC, Ac, aC, ac as your gamete sets of alleles?
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    (Original post by enaayrah)
    My friend messaged me with a similar question just the other day...

    When you initially crossed aaCC and AAcc, did you use the combinations AC, Ac, aC, ac as your gametes?
    Indeed
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    (Original post by enaayrah)
    My friend messaged me with a similar question just the other day...

    When you initially crossed aaCC and AAcc, did you use the combinations AC, Ac, aC, ac as your gamete sets of alleles?
    Oh I think I've got it now.

    It is recessive epistasis, because the gene C/c must be cc in order to mask the production of the colour pigment.

    Is that right?
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    (Original post by kingaaran)
    Indeed
    Hmm then I have no clue
    I hope someone comes and clears this up for you
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    (Original post by kingaaran)
    Oh I think I've got it now.

    It is recessive epistasis, because the gene C/c must be cc in order to mask the production of the colour pigment.

    Is that right?
    After googling recessive and dominant epistatis, that sounds right, I think

    I've never come across epistasis before
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    (Original post by enaayrah)
    After googling recessive and dominant epistatis, that sounds right, I think

    I've never come across epistasis before
    Yay!

    It's tricky but a tonne of fun - genetics is quite interesting
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    (Original post by kingaaran)
    Yay!

    It's tricky but a tonne of fun - genetics is quite interesting
    Omg do you OCR? For some reason, I find the inheritance enjoyable as well!
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    (Original post by Kamara7)
    Omg do you OCR? For some reason, I find the inheritance enjoyable as well!
    Yeah I do OCR!
 
 
 
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