The proportion of a population suffering from a specific rar

The proportion of a population suffering from a specific rare genetic disease is 0.02%. Assume that the disease is caused by a single recessive allele and assume that the population is in HWE. How many individuals carry the disease allele in the heterozygous state? How do you know?!

Solution

Answer:

The disease frequency (qq) = 0.02% = 0.0002

The diseased allele frequency (q) = Root of 0.0002 = 0.014

p+q=1

p = 1-0.014 = 0.986

The normal dominant allele frequency (p)= 0.986

The heterozygous frequency (2pq) = 2* 0.986* 0.014=0.028

The heterozygous individuals = 0.028 * 100 = 2.8

Almost three individuals carry the disease allele in the heterozygous state.