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Homework Help: Genetics - independent assortment and linkage

  1. Oct 14, 2007 #1
    1. The problem statement, all variables and given/known data
    In a testcross in D. melanogaster, the female heterozygote shv+/shv ; he+/h+e is crossed to a male from the homozygous recssive stock, shv/shv ; he/he.

    What proportion of the hairy-bodied flies has short veins? What event during meiosis causes this? How does the occurrence or non-occurrence of a recombinant event affect your answer?

    (h=hairy body, e=ebony body, shv=short-veined)

    2. Relevant equations

    3. The attempt at a solution
    Independent assortment of alleles in Metaphase I causes this. A recombinant event does not occur between the two genes because the genes are unlinked, so there is no recombination frequency to take into consideration.

    I was wondering if someone could check my thinking on this. This was a question on an assignment that I handed in and got back - my TA has written that the answer is actually 1/4. If it's needed, we found in an earlier part of the question that 1/5 of the gametes in the female are recombinant. But I thought you could just deal with shv separately than h and e since it's on a different chromosome, and shv+/shv x shv/shv = 1/2 shv+/shv and 1/2 shv/shv.
  2. jcsd
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