Question

A gene locus has two alleles $A,a$. If the frequency of dominant allele A is $0.4$, then what will be the frequency of homozygous dominant, heterozygous and homozygous recessive individuals in the population ?

• A. $0.16(AA);0.48(Aa):0.36(aa)$
• B. $0.16(AA);0.36(Aa);0.48(aa)$
• C. $0.36(AA);0.48(Aa);0.16(aa)$
• D. $0.16(AA);0.24(Aa);0.36(aa)$

Answer 1

Answer: (A)

Frequency of dominant allele (say p) $=0.4$
Frequency of recessive allele (say q)
$=1-0.4=0.6$
$\therefore$ Frequency of homozygous dominant individuals $(AA)$
= $p^2=(0.4{)}^2=0.16$
Frequency of heterozygous individuals (Aa)
$=2pq=2(0.4)(0.6)=0.48$
Frequency of homozygous recessive individuals $(aa)$
$=q^2=(0.6{)}^2=0.36$