Someone PLEASE help me understand this biology question!!!!!!!!

Discussion in 'Random Ramblings' started by Heather118, Nov 26, 2011.

  1. Heather118

    Heather118 Out Of The Brooder

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    The question is: What is implied by a 1:2:1 phenotypic ratio in the F2 generation of a monohybrid cross? Thank you so much!!!!!!!!!
     
  2. Heather118

    Heather118 Out Of The Brooder

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    Quote:That is so embarrassing! I did google it, but I must have phrased it strangely or something, because I didn't find an answer. Thanks for your help!
     
  3. Oregon Blues

    Oregon Blues Overrun With Chickens

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    The answer to that would be found in your biology textbook.
     
  4. RaZ

    RaZ Overrun With Chickens Premium Member

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    It's the offspring of heterozygous parents; (Pp) crossed with (Pp)
    The offspring turn out as 1 PP; 2 Pp and 1 pp.

    Say that P is the dominant gene for purple and p is recessive for pink. Both parents are purple and the F2 will be 3 purple and 1 pink progeny. The colour is the phenotype (appearance).
     
  5. dfr1973

    dfr1973 Chillin' With My Peeps

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    Raz, that is the proper genotypic breakdown for simple (classic) Mendelian autosomal recessive ... and also what I first thought to post. Thankfully I observed my "no serious posts before 2nd cup of coffee" rule, as her question has the 1:2:1 phenotypic result in F2. While the first link listed mentions incomplete dominance, and gives the red and white flowers (sometimes) equaling pink progeny, the other option is codominance, where red and white flowers result in F1s sporting both colors (iirc, this one is snapdragons versus pea flowers? Where DID I put my genetics textbook?)

    Using flowers, and (hopefully) illustrating the incomplete dominance:
    P gen (parental generation): RR (red phenotype) x WW (white phenotype)
    F1 (first hybrid cross): all RW (pink phenotype)
    F2 (second generation cross): 1 RR (red) : 2 RW (pink) : 1 WW (white)

    NB: To get full credit from both my gen bio and my genetics professors, accompanying Punnett squares had to be drawn [​IMG]

    Heather, does this help?
     
  6. rancher hicks

    rancher hicks Chicken Obsessed

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    Quote:HUH??? You lost me at the word "implied" [​IMG]

    I'm to old for this crap, (it's my new mantra)

    Rancher
     
  7. RaZ

    RaZ Overrun With Chickens Premium Member

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    Quote:That's what I get for reading too quickly and not checking my work. I think I should adopt your posting philosophy. In the mean time, I'm blaming senoritis and too much homework. [​IMG]
     
  8. Clay Mudd

    Clay Mudd Chillin' With My Peeps

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    Quote:But that would be cheating. [​IMG]
     
  9. Oregon Blues

    Oregon Blues Overrun With Chickens

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    I am assuming that the OP has that question in their biology home work and is too lazy to look it up. There is no reason to be giving a quiz to the rest of us.
     

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