anatomy
Forum Guru
Topics: 101
Posts: 423
|
A woman with cystic fibrosis marries her first cousin.
whats the risk that their first child will have CF
1/2
1/4
1/8
1/16
1/32
Please explain the ans
|
| almina
Forum Senior
Topics: 34
Posts: 99
|
the woman with cystic fibrosis - aa
the cousin she married - Aa/AA(there is no evidence he has the disease)
Their child could be 100% carrier in case that his father is AA, or
the child can have 50% chance to be a carrier and 50%chance to have the disease,
so the answer is - 1/2
|
| anatomy
Forum Guru
Topics: 101
Posts: 423
|
any one else pls explain me.
|
| skylark
Forum Newbie
Topics: 0
Posts: 21
|
im not sure of the answer, but i think if the cousin would be AA there are 0 chances. if he is aa all the kids will have the disease. now if he is Aa there is a 50% chance or 1/2. they're first cousins so they share 1/8 of their genes. so i would say 1/16. whats the answer?
|
| newfriend
Forum Newbie
Topics: 5
Posts: 30
|
i think Almina answer is the correct one
|
| blinx420
Forum Newbie
Topics: 0
Posts: 2
|
A woman with cystic fibrosis marries her first cousin.
whats the risk that their first child will have CF?
The woman is aa. Therefore her parents are Aa x Aa. Therefore, her grandparents must have been AA x Aa (they could also be Aa x Aa but this is a small probability so we can ignore it).
Now, the probability that the woman's aunt (or uncle or whatever) is Aa is 1/2. The aunt will marry a man who is AA. So the probability that the cousin will be Aa is 1/2.
Now, the probability that the woman (aa) and the cousin (Aa) have a aa child is 1/2.
Therefore the probability that all this happens is 1/2 x 1/2 x 1/2 = 1/8
|
| merrk
Forum Elite
Topics: 27
Posts: 280
|
Acc to Kaplan cousins share 1/8th of genes
mother is aa cousin has 1/8th chance of being a carrier
so 1/8 X 1/2 = 1/16
___________________
It is not your aptitude but your attitude that determines your altitude in life
|
|
| |
| | | | | | | |
