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Jackofknives
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08/14/07 - 08:23 AM

A man and woman are both affected by an autosomal dominant disorder that has 80% penetrance in all affected individuals. They are both heterozygotes for the disease-causing mutation. What is the probablity that they will produce phenotypically normal offspring?

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new_n_lost
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08/14/07 - 01:09 PM

.25% i hope i m right but in any case Jack Can u plz post the answer and the explanation that goes along with it.

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doc179
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08/14/07 - 01:18 PM

25% would have been the answer if it had 100% penetrance but since it has 80% penetrance so that would be 40 % unaffected and 60% affected. Hope I am right.

MALUKO
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08/14/07 - 01:35 PM

Probability that the child will be affected is (.75)(.80) = .60

Probability that the child will not be affected 1 - .60 = .40

I only know it because I got it wrong. grin

bzhishk
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08/14/07 - 03:38 PM

0.25+(0.75x0.20)=0.4 or 40 %

Jackofknives
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08/15/07 - 01:07 AM

MALUKO wrote:
Probability that the child will be affected is (.75)(.80) = .60

Probability that the child will not be affected 1 - .60 = .40

I only know it because I got it wrong. grin

This is the explanation.

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the seeker
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11/22/07 - 09:52 AM

great explanation..thanks so much

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