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#1
10-01-2014
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83
challenging Genetic Q

this q is driving me crazy i dont know how to use Hardy Weinberg in this ?
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 The above post was thanked by: israaoday (10-01-2014)

#2
10-01-2014
 USMLE Forums Addict Steps History: 1+CK+CS Posts: 101 Threads: 2 Thanked 45 Times in 34 Posts Reputation: 55

is it 0.05?
#3
10-01-2014
 USMLE Forums Addict Steps History: 1 + CK Posts: 143 Threads: 12 Thanked 59 Times in 38 Posts Reputation: 69

I got 0.05
Prevalence=q2=1/100 so q=1/10
Carrier freq= 2q=2×1/10=0.2

Probability man transmit dis allele=1/2
Probability woman is a carrier=0.2
Probability woman transmit dis allele= 1/2

Multiply....1/2×0.2×1/2= 0.05
 The above post was thanked by: DrNewB (10-02-2014)
#4
10-01-2014
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83

Quote:
 Originally Posted by Fereshteh is it 0.05?
yes u r right but explain please?
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#5
10-01-2014
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83

Quote:
 Originally Posted by excellence Probability man transmit dis allele=1/2 Probability woman transmit dis allele= 1/2 Multiply....1/2×0.2×1/2= 0.05
but how did u get those? and why then multiply?
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#6
10-01-2014
 USMLE Forums Scout Steps History: Not yet Posts: 71 Threads: 15 Thanked 47 Times in 27 Posts Reputation: 57

Quote:
 Originally Posted by swwal but how did u get those? and why then multiply?
we multiplied because what we need is overall probabality.
#7
10-01-2014
 USMLE Forums Guru Steps History: Not yet Posts: 304 Threads: 76 Thanked 73 Times in 51 Posts Reputation: 83

Quote:
 Originally Posted by Panmedic we multiplied because what we need is overall probabality.
Probability man transmit dis allele=1/2

Probability woman transmit dis allele= 1/2

is not supposed to be 25% = 1/4 ?! bcz this is recurrence risk of AR
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#8
10-01-2014
 USMLE Forums Addict Steps History: 1 + CK Posts: 143 Threads: 12 Thanked 59 Times in 38 Posts Reputation: 69

Quote:
 Originally Posted by swwal Probability man transmit dis allele=1/2 Probability woman transmit dis allele= 1/2 is not supposed to be 25% = 1/4 ?! bcz this is recurrence risk of AR
also you need to multiply the probability of the mother to be a carrier for the diseased allele because in the question they mentioned she is from the general population, so you dont know if she's a carrier or not...so you should calculate her carrier probability by using HW equation...

at the end u multiply all the probabilities
#9
10-01-2014
 USMLE Forums Scout Steps History: Not yet Posts: 29 Threads: 6 Thanked 3 Times in 3 Posts Reputation: 13

Quote:
 Originally Posted by excellence I got 0.05 Prevalence=q2=1/100 so q=1/10 Carrier freq= 2q=2×1/10=0.2 Probability man transmit dis allele=1/2 Probability woman is a carrier=0.2 Probability woman transmit dis allele= 1/2 Multiply....1/2×0.2×1/2= 0.05
Did you asume p =1 in your calculations? So carrier frequency is 2pq =2x1x1/10
#10
10-01-2014
 USMLE Forums Addict Steps History: 1 + CK Posts: 143 Threads: 12 Thanked 59 Times in 38 Posts Reputation: 69

Quote:
 Originally Posted by dr_marini Did you asume p =1 in your calculations? So carrier frequency is 2pq =2x1x1/10
Yes I did.
#11
10-01-2014
 USMLE Forums Scout Steps History: Not yet Posts: 29 Threads: 6 Thanked 3 Times in 3 Posts Reputation: 13

thank you.

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