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#1
05-16-2011
 USMLE Forums Guru Steps History: Step 1 Only Posts: 343 Threads: 127 Thanked 522 Times in 192 Posts Reputation: 532
Calculating Allele Frequency from Genotype Frequencies?

A population has been assayed for a four-allele polymorphism, and the following genotype counts have been obtained..

Genotype Count
--------------------------------------------------------------------
1,1 = 4
1,3 = 8
1,4 = 3
2,3 = 5
2,4 = 9
3,3 = 4
3,4 = 6
4,4 = 11

On the basis of these genotype counts what are gene frequencies of alleles 1 , 2

A) 0.38, 0.28
B) 0.19, 0.14
c) 0.095, 0.07
d) 0.38, 0.20
e)

i am sure answer is not option e

#2
05-16-2011
 USMLE Forums Master Steps History: 1+CK+CS+3 Posts: 1,357 Threads: 194 Thanked 3,259 Times in 881 Posts Reputation: 3269

I think is B)
#3
05-16-2011
 USMLE Forums Guru Steps History: Step 1 Only Posts: 343 Threads: 127 Thanked 522 Times in 192 Posts Reputation: 532

ya u are right
what about gene frequency of allele 4
#4
05-22-2011
 USMLE Forums Veteran Steps History: --- Posts: 250 Threads: 19 Thanked 43 Times in 39 Posts Reputation: 53

Quote:
 Originally Posted by bebix I think is B)

#5
05-22-2011
 USMLE Forums Master Steps History: 1+CK+CS+3 Posts: 1,357 Threads: 194 Thanked 3,259 Times in 881 Posts Reputation: 3269

Quote:
 Originally Posted by star123 can you explain the answer please... i dun get it
Genotype Count
--------------------------------------------------------------------
1,1 = 4
1,3 = 8
1,4 = 3
2,3 = 5
2,4 = 9
3,3 = 4
3,4 = 6
4,4 = 11

frequencies of allele 1
count the number of "1"
row 1 = 4 + 4
row 2 = 8
row 3 = 3
= 19

divided by the total =
(4+8+3+5+9+4+6+11)*2 = 100

19 / 100 = 0.19

frequencies of allele 2
5 + 9 = 14
14 / 100 = 0.14
 The above post was thanked by: AishwaryaDurgaR (12-05-2015)
#6
05-23-2011
 USMLE Forums Guru Steps History: Step 1 Only Posts: 343 Threads: 127 Thanked 522 Times in 192 Posts Reputation: 532

similarly as i asked what is gene frequency of allele 4

3+9+6+22= 40
40/100=0.4

plz correct me if i m wrong

Last edited by INCOGNITO; 05-23-2011 at 04:29 PM.
 The above post was thanked by: bebix (05-23-2011)
#7
05-23-2011
 USMLE Forums Master Steps History: 1+CK+CS+3 Posts: 1,357 Threads: 194 Thanked 3,259 Times in 881 Posts Reputation: 3269

why 200?

I think the correct answer is:

allele 4
40/100
 The above post was thanked by: INCOGNITO (05-23-2011)
#8
05-23-2011
 USMLE Forums Guru Steps History: Step 1 Only Posts: 343 Threads: 127 Thanked 522 Times in 192 Posts Reputation: 532

Quote:
 Originally Posted by bebix why 200? I think the correct answer is: allele 4 40/100
ya u are right
i corrected ma last post

 Tags Genetics-, Step-1-Questions

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