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Homework Help: Mendelian crossings problems

  1. Feb 7, 2007 #1
    I GOT IT nevermind thanks

    i would really appreciate some help on this,
    swamped with studies and my brain won't wrap around the mendelian gene crossings

    here's one:
    Base height of a plant is 10 cm. Four genes contribute to the height, and each dominant allele contributes 3 cm to height. If you cross a 10-cm plant (quadruply homozygous recessive) with a 34-cm plant, how many phenotypic classes will there be in the F2?

    so i subtracted 10 from 34 =24. Dividing by 3 I get 8- so does that mean 8 dominant alleles present in one of the parents? don't really know where to go from there..


    and another:
    In guinea pigs the brown coat color allele (B) is dominant over red (b), and the solid color allele (S) is dominant over spotted (s). The F1 offspring of a cross between true-breeding brown, solid-colored guinea pigs and red, spotted pigs are crossed. What proportion of their offspring (F2) would be expected to be red and solid colored?

    -so is one of the F1 BBSS? And the other bbss? So I don't understand how I can get a red?
     
    Last edited: Feb 7, 2007
  2. jcsd
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