AP Biology help?

Question

A population has 8 times as many heterozyotes as homozygous recessives. What is the frequency of the recessive gene?

A recessive characteristic appears in 40% of males and 16% of females. What kind of trait is it? Frequency of heterozygous females? heterozygous males? males not showing the characteristic?
*PPPPPlllleeeaaseee! I really need help with them!

Answer 1

Using Hardy-Weinberg,
a^2 + 2ab + b^2 = 1

ab=8 b^2
ab/b = 8*b*b/b
a = 8b
Substitute 8b for a in the Hardy-Weinberg equation.

a^2 + 2ab + b^2 = 1
8b*8b + 2*8b*b + b*b = 1
64 b^2 + 16 b^2 + b^2 = 1
81 b^2 = 1
b^2 = 1/81
b = 1/9 = 0.11 = frequency of recessive gene.

There's probably an easier way to do that problem, but that's what I have for you.

Second question - sounds like a sex-linked trait, but it's my dinner time right now. Good luck.

Answer 2

Aa 8 times or 16 alleles 1/2 x 16 alleles are a
aa once or 1x 2 alleles are a
pop of 9 gives 18 alleles

a = 2+8/18 = .56

A recessive trait showing on males more than females
would indicate an x linkage. Then for males, gene and genotype frequencies are the same since they only have one x.