# Good OL Hardy

#### RockstarDMD

##### sUcCeSs iS mY OnLY OpTioN
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5+ Year Member
Ok I don't know why this problem is giving me difficulties, but it is.

If the frequency of the dominant allele D is three times that of the recessive allele d. What is the frequency of heterozygotes in the population?

6.25%
25%
37.5%
56.25%
75%

#### tuan209

##### Member
10+ Year Member
7+ Year Member
RockstarDMD said:
Ok I don't know why this problem is giving me difficulties, but it is.

If the frequency of the dominant allele D is three times that of the recessive allele d. What is the frequency of heterozygotes in the population?

6.25%
25%
37.5%
56.25%
75%

I think its 37.5%. 1x + 3x = 1. x = .25 p=.75 q=.25
heterozygotes = 2 X (.25)(.75) = 37.5%

#### dat_student

##### Junior Member
10+ Year Member
5+ Year Member
RockstarDMD said:
Ok I don't know why this problem is giving me difficulties, but it is.

If the frequency of the dominant allele D is three times that of the recessive allele d. What is the frequency of heterozygotes in the population?

6.25%
25%
37.5%
56.25%
75%

37.5%

D + d = 1

3d + d = 1

4d = 1

d = 1/4
D = 3/4

2(D)(d) = (2)(3/4)(1/4) = 0.375 or 37.5%

#### tinman831

##### ¯\_(ツ)_/¯
Staff member
15+ Year Member
RockstarDMD said:
Ok I don't know why this problem is giving me difficulties, but it is.

If the frequency of the dominant allele D is three times that of the recessive allele d. What is the frequency of heterozygotes in the population?

6.25%
25%
37.5%
56.25%
75%

p = frequency of allele D
q = frequency of allele d

p + q = 1

if p is 3 times the frequency of q, then p = .75 and q = .25

Frequency of Aa in the population is = 2pq

2*.75*.25 = .375

#### tinman831

##### ¯\_(ツ)_/¯
Staff member
15+ Year Member
Gosh I am too slow.

OP

#### RockstarDMD

##### sUcCeSs iS mY OnLY OpTioN
10+ Year Member
5+ Year Member
dat_student said:
37.5%

D + d = 1

3d + d = 1

4d = 1

d = 1/4
D = 3/4

2(D)(d) = (2)(3/4)(1/4) = 0.375 or 37.5%
You are both correct thank you for your prompt responses.

OP

#### RockstarDMD

##### sUcCeSs iS mY OnLY OpTioN
10+ Year Member
5+ Year Member
Tinman thanks for your response as well, even though you were slow to the draw.