Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Help with a VERY HARD genetics question PLEASE?

  1. Apr 27, 2004 #1
    I'm a first-year college student and I'm havnig a lot of trouble with a particular question. Here goes:

    Manx cats are tailess and when crossed with one another produceo n averaeg one long-tailed cat for every 2 Manx. The allele is lethal in homozygous condition due to problems arisiging in development of the lower vertebrae.

    Suppose an island were populated with Manx cats.

    (a) What would the ferquency of Manx allele be in first generation zygotes produced by the founders? Indciate as completely as possible your argument for this and the next question?

    (b) What would the frequency of the Manx allele be in breeding age individuals of thsi generation?

    (c) What process is under study in this change in allele frequencies (one sentence or phrase only)?
     
  2. jcsd
  3. Apr 27, 2004 #2
    What are your own answers so far?
     
  4. Apr 27, 2004 #3
    For (a), my friends and I came up with:

    Aa X aa --> 2 tailess (Aa) + 2 long-tailed (aa)
    Manx allele = A (dominant)

    Frequency = 2A/(6a + 2A) = 2/8 = 1/4 = 0.25

    For (b):

    The number of individuals can be calculated by:

    2Aa = 2 X 0.25 (1-0.25) = 0.375

    For (c):

    Genetic drift??

    I'm not sure if any of the our answers are right. Any help will be much appreciated. THANKS!!
     
  5. Apr 27, 2004 #4

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    I'll offer some help with part (a) and see how things go from there. You're right that Manx cats are heterozygotes, and in this example appears to be a dominant trait. However, take careful note of the founders for part (a). The problem states that the island is populated with Manx cats, not a mix of Manx and cats with tails. So your founders are all heterozygotes, not a cross of heterozygotes and homozygotes. See how that affects your calculations.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Help with a VERY HARD genetics question PLEASE?
  1. A Genetics Question (Replies: 3)

  2. Genetics Question (Replies: 4)

  3. Genetic. Help (Replies: 4)

Loading...