Hardy Weinberg (HW) Genetic Frequency Question (Please help)

[zafina112]

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Hi there,

I have a tricky question that I can't seem to figure out, hopefully someone can help me!

Question:
A population where 9% of the men are red green colour blind, what are the expected proportions of genotypes for the males and females? In a community of 354 individuals, how many women are expected to have the colour vision deficiency?

What I have so far....

X^hY will represent red green colour blind for males
X^hX^h will represent recessive colour blind for females
X^HX^h will represent heterozygous (carrier) for the colour blind disease for females
X^HX^H will represent normal females

How do i figure out the number of women who have colour blind?

 

[zafina112]

Can someone please help me?!

I don't know if it is correct or not, but...

since 9% of the men are red green colour blind which means

f(X^hY) = 9% = 0.09 is q
- then I square root 0.09 = 0.3

p+q=1
p= 1 - 0.3
p = 0.7

X^HX^H = (p)(p) = p^2
= (0.7)(0.7)
= 0.49

X^HX^h = (pq)(pq) = 2pq
= 2(0.3)(0.7)
= 0.42

X^hX^h = (q)(q) = q^2
= (0.3)(0.3)
=0.9

I don't know if this is correct, but does this mean 9% of the females in a community will get colour blind?
I just need some direction on this

 

[adrakdavra]

Hardy–Weinberg law states that both allele and genotype frequencies in a population remain constant—that is, they are in equilibrium—from generation to generation unless specific disturbing influences are introduced.
In a Sex Link problem The females pass thier X link to the males with the same ratio, so if the males are .09 the female will also be .09. This will be my guess !

 

[cortana431]

Your work is correct. (Except q^2 should be .09 in the last line so that p^2+2pq+q^2=1.) And yes, allele frequencies are equal for males and females.

 

[zafina112]

Your work is correct. (Except q^2 should be .09 in the last line so that p^2+2pq+q^2=1.) And yes, allele frequencies are equal for males and females.

So it would mean that q^2 = (0.09)(0.09) = 0.0081
So it would be 0.81%?
And within a community of 354, there would be 2.87 (3.00) women that would have colour blindness because it would be 354 x 0.0081.

Hopefully this is correct.