Question

The Hardy-Weiberg equation for a gene with two alleles is as follows: ${p^2} + 2pq + {q^2} = p + q = 1$.
Which part of the equation represents the frequency of one of the alleles?
A. $2pq$
B. $p$
C. ${p^2}$
D. ${p^2} + 2pq$

Answer 1

The Hardy-Weiberg’s equation of Hardy-Weiberg's equilibrium is used for the estimation of frequency of alleles in an equation.

Complete answer:
The Hardy-Weiberg equation is used to estimate the frequency of alleles in a population.
For a population in genetic equilibrium,
$p + q = 1.0$. . . . . (1), this means that sum of frequencies of both alleles is $100\% .$ $p$ is the dominant allele and $q$ is recessive allele ensuring both sides for $p + q = 1.0,$
We get ${\left( {p + q} \right)^2} = {(1.0)^2}$
${p^2} + 2pq + {q^2} = 1.0$. . . . . (2)
These three terms express the frequencies of three genotypes. In the equation (2), ${p^2}$ is the frequency of a homozygous dominant allele. Whereas ${q^2}$is the frequency of homozygous recessive allele. $2pq$ is the frequency of heterozygous alleles. The two or more alternative forms of a gene are called alleles. Allele regulates the expression of character. The two types of alleles are:
(a) Homozygous allele: When the offspring inherits a similar pair of alleles from both the parent’s. It is called homozygous allele.
Example: When offspring receive the same allele T and T-form parents they form a pair of TT. Which is for tallness of plants.
(b) Heterozygous allele: When the offspring inherit different genes from both parents. It leads to the formation of a heterozygous pair of alleles. Example: If one parent inherts ‘T’ for tallness and one parent inherts ‘t’ for tallness then the offspring will receive. It is different in expression and so is called heterozygous. In Hardy-Weinberg equation ${p^2} + 2pq + {q^2} = 1,$ can express the frequency of one of the alleles as ${p^2}$represent frequency of heterozygous genotype.

Therefore, from the above explanation the correct answer is option is (B) $p.$

Note: A pair of allele is responsible for expression of character. A character that can express itself is called dominant. Whereas the character that remains suppressed is called recessive.