Question

The frequency of an autosomal recessive gene in a population is $\mathrm{0.40.}$ The number of carriers in a population of 2000 individuals is

• A. $720$
• B. $960$
• C. $1040$
• D. $360$

Answer 1

The correct option is B $960$

Hardy-Weinberg principle says that allele frequency in a population are stable and is constant from generation to generation. The gene pool remains constant. Sum total of all the allelic frequencies is 1. In a diploid, p and q represent the frequency of allele A and allele a. The frequency of AA is p2. The equation is p2+2pq+q2=1. The frequency of the an autosomal recessive gene in a population is 0.04 (given q). p=1-0.4=0.6. (0.6)2 + 2pq + (0.4)2 = 1. 0.36+ 2pq + 0.16= 1. 0.52 + 2pq=1. 2pq=0.48. Since 2pq is the frequency of the heterozygous carrier. 2pq=0.48X2000 = 960.

So, the correct option is '960'.