Question

Let’s say that 64% the people on an island are get a rash when they touch a poisonous plant. studies have shown that these people must have at least one copy of a particular dominant allele. what percentage of the population must be heterozygous for this trait if this population conforms to hardy-weinberg expectations for this gene?

Answer 1

We are given with
p2 + 2pq = 0.64
and another formula is
p2 + 2pq + q2 = 1
Substituting
0.64 + q2 = 1
q2 = 1 - 0.64
q2 = 0.36
q = 0.6

Another formula is
p + q = 1
p = 1 - 0.6
p = 0.4

What is asked is 2pq
p2 + 2pq = 0.64
2pq = 0.64 - 0.4^2
2pq = 0.48

There is 48% that has the heterozygous trait.