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Homework Help: Help to two pedigrees

  1. Dec 5, 2009 #1
    I need help to the following two pedigrees:

    squares = men and circles = women
    green = healthy and yellow = sick

    Task 1:

    a) What is the mode of inheritance? Why?

    b) What are the genotypes of each individual?

    http://img21.imageshack.us/img21/9991/pedigree.gif [Broken]

    Task 2:

    a) What is the mode of inheritance? Why?

    b) What are the genotypes of each individual?

    c) What proportion of the offspring from individual III-1 and III-2 are likely to have the disease?

    d) What proportion of the offspring from individual III-6 and III-7 are likely to have the disease?

    http://img268.imageshack.us/img268/9991/pedigree.gif [Broken]
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Dec 5, 2009 #2
    Hi,
    Task 1:
    First note the gonosomes of each individual.
    Then look at the first male what does he give to his daughter?
    What happens then his allele is dominant? What happerns if the allele is recessive?
    Afterwards take a look at the sick individuals: What do you see?
    Is there a connection to the gonosomes?

    Task 2
    Repeat the steps from Task 1

    I hope I could help you,
    Firelion
    PS: If you notice a mistake in my language: please correct me.
     
  4. Dec 5, 2009 #3
    Task 1:

    a) Autosomal recessive/x-linked recessive.

    b)

    If it is autosomal:

    I. aa; AA; aA; aA
    II. aA; aA; aA or AA; aa
    III. aa

    If it is x-linked:

    I. xY; XX; XY; xX
    II. xX; XY; xX; XY; xY
    III. xY

    http://img21.imageshack.us/img21/9991/pedigree.gif [Broken]

    Task 2:

    a) Autosomal dominant.

    b)

    I. AA; aa
    II. aa; aA; aA; aa
    III. aa; aA; aa; aA; aa; aA; aA; aA; aa; aa

    c) What proportion of the offspring from individual III-1 and III-2 are likely to have the disease?

    aA x aa = 2/4 = 50 percent.

    d) What proportion of the offspring from individual III-6 and III-7 are likely to have the disease?

    aA x aA = 3/4 = 75 percent.

    http://img268.imageshack.us/img268/9991/pedigree.gif [Broken]
     
    Last edited by a moderator: May 4, 2017
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