5. Tay-Sachs disease is caused by a recessive allele. The frequency of this allele is 0.1 in a population of 3600 people. What is the frequency of the dominant allele, and how many of the 3600 people will be heterozygous for the condition

The frequency of the dominant allele is 0.9 and there will be 648 heterozygous people for the condition.

Explanation:

According to Hardy Weinberg`s equilibrium p2 + 2pq + q2 = 1  

p = frequency of the dominant allele in the population

q = frequency of the recessive allele in the population

p2 = percentage of homozygous dominant individuals

q2 = percentage of homozygous recessive individuals

2pq = percentage of heterozygous individuals = frequency of the dominant allele

Therefore (1 - 0.1) = 0.9. (frequency of dominant allele)

(0.18x3600) = 648 (number of peopleheterozygous for Tay Sachs, 18% of the population).