A gene locus has two alleles A, a. If the frequency of dominant allele A is 0.4, then what will be the…

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?
  1. 0.36(AA); 0.48(Aa); 0.16(aa)
  2. 0.16(AA); 0.24(Aa); 0.36(aa)
  3. 0.16(AA); 048(Aa); 0.36(aa)
  4. 0.16(AA); 0.36(Aa); 0.48(aa)

Solution

According to the Hardy-Weinberg principle: 

Frequency of dominant allele (A) = p =0.4

Frequency of recessive allele (a) = q  

Sum total of all the allelic frequencies is 1, i.e. p+q = 1 

⇒  0.4 + q = 1 

⇒  q = 0.6                                       

Frequency of AA individuals = p × p = p2 = (0.4)2 = 0.16

Frequency of aa individuals = q × q = q2 = (0.6)2 = 0.36

Frequency of Aa individuals = 2pq = 2(0.4)(0.6) = 0.48

Asked in: NEET 2019 (All India)

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