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#1
04-17-2012
 USMLE Forums Master Steps History: 1+CK+CS Posts: 1,406 Threads: 118 Thanked 647 Times in 409 Posts Reputation: 657
Simple Genotype Frequency Calculation

What is the frequency of the Aa genotype and the AA genotype if the frequency of allele A is 0.9%?
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#2
04-17-2012
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p = 0.9
q = 0.1

prevalence of Aa genotype is 2pq = 0.1
prevalence of AA genotype is p^2 = 0.81
 The above post was thanked by: Dr.NickRiviera (04-18-2012), Valkoff (04-18-2012)
#3
04-17-2012
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Quote:
 Originally Posted by Dr.NickRiviera What is the frequency of the Aa genotype and the AA genotype if the frequency of allele A is 0.9%?
Carrier Freq = 2Aa = 2(0.9)(0.1)
Dominet Freq = A^2 = (0.9)^2
 The above post was thanked by: Dr.NickRiviera (04-18-2012), Valkoff (04-18-2012)

#4
04-18-2012
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How did we calculate q to be 0.1?
#5
04-18-2012
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Quote:
 Originally Posted by Valkoff How did we calculate q to be 0.1?
p^2 + 2pq + q^2 = 1

Allel prevalance is p + q = 1
 The above post was thanked by: Valkoff (04-18-2012)
#6
04-18-2012
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I sat for a while, trying to remember how to do quadratic equations!
#7
04-18-2012
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Quote:
 Originally Posted by johndoe3344 p = 0.9 q = 0.1 prevalence of Aa genotype is 2pq = 0.1 prevalence of AA genotype is p^2 = 0.81
isn't its more close to .2 than .1?
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#8
04-18-2012
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To use the p2 + 2pq + q2, it has to be in equilibrium. How would you just assume that the population is in hardy weinberg equilibrium ? Although I'm pretty sure that this is the way to calculate it ...
#9
04-18-2012
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Quote:
 Originally Posted by Hope2Pass To use the p2 + 2pq + q2, it has to be in equilibrium. How would you just assume that the population is in hardy weinberg equilibrium ? Although I'm pretty sure that this is the way to calculate it ...
Isn't the this is the case unless otherwise mentioned ?
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#10
04-18-2012
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Quote:
 Originally Posted by Kabutar111 isn't its more close to .2 than .1?
Yeah it should be 0.18 = 2pq = Aa
#11
04-18-2012
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Quote:
 Originally Posted by johndoe3344 p = 0.9 q = 0.1 prevalence of Aa genotype is 2pq = 0.1 prevalence of AA genotype is p^2 = 0.81
Yeah, 0.18, my bad. Left out the 8 =/

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