Solve Pedigree Problems: Task 1 & 2

[LifestyeleOrk]

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

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

 

[Firelion]

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.

 

[LifestyeleOrk]

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

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