Question

In a large isolated population, alleles p and q at a locus are at Hardy Weinberg equilibrium. The frequencies are p = 0.6 and q = 0.4. The proportion of the heterozygous genotype in the population is:
A. 0.24
B. 1
C. 0.48
D. 0.12

Answer 1

Hint: We have to know that the Hardy-Weinberg equilibrium is a theory which states that in the absence of disturbing factors, genetic variation in a population will remain constant from one generation to the next. Gene flow, which occurs when new alleles are transferred into a population by breeding between two populations, may alter the Hardy-Weinberg equilibrium.

Complete answer:
As we know that the Hardy-Weinberg equilibrium theory explains that the genetic variation in a population will remain constant from one generation to the next if there is absence of disturbing factors. For example, by the introduction of new alleles into a population, mutations disturb the equilibrium of allele frequencies.
This problem can be solved using the Hardy-Weinberg equation.
q2 symbolizes the frequency of homozygous recessive creatures.
As q = 0.4, q2 = 0.16.
$\Rightarrow$ p + q = 1
$\Rightarrow$ 1 - 0.4 = p
$\therefore$ p = 0.6.
Accordingly the frequency of homozygous dominant organisms p2 = 0.36.
We have to remember that the frequency of heterozygous plants is represented by (2pq). For this reason 2(0.6) (0.4) = 0.48.
So, the correct answer is “Option c”.

Note:
For example, by the introduction of new alleles into a population, mutations disturb the equilibrium of allele frequencies. Similarly, the Hardy-Weinberg equilibrium is broken by natural selection and nonrandom mating because they result in shifts in gene frequencies. This happens because the reproductive success of the species that bear them is supported or harmed by such alleles. Genetic drift, which occurs as allele frequencies grow higher or lower by chance and usually takes place in small populations, is another aspect that may disrupt this equilibrium.