91Ó°ÊÓ

If the observed and expected genotype frequencies are similar in a population, then the population is in Hardy-Weinberg equilibrium. Selection can act and affect the genotype frequencies. In the absence of selection, the genotype frequency expected and observed remains the same.

To calculate: Observed frequencies of genotypes \({C^G}{C^G}\),\({C^G}{C^Y}\), and\({C^Y}{C^Y}\)at Day 7.

From the observed frequencies from day 7, it is given that:

Number of homozygous dominant or green seedlings (\({C^G}{C^G}\))= 49

Total number of seedlings= 216

The observed genotypic frequency of\({C^G}{C^G}\)(\({p^2}\)) is:

\({p^2} = \frac{{Number{\rm{ }}of{\rm{ }}homozygous{\rm{ }}dominant{\rm{ }}or{\rm{ }}green{\rm{ }}seedlings{\rm{ }}\left( {{C^G}{C^G}} \right)}}{{Total{\rm{ }}number{\rm{ }}of{\rm{ }}seedlings}}\)

\(\begin{aligned}{l}{p^2} &= \frac{{49}}{{216}}\\{p^2} &= 0.226\\{p^2} &= 0.23\end{aligned}\)

From the observed frequencies from day 7, it is given that:

Number of heterozygous genotypes or green-yellow seedlings (\({C^G}{C^Y}\))= 111

Total number of seedlings= 216

The observed genotypic frequency of\({C^G}{C^Y}\)(\(2pq\)) is:

\(2pq = \frac{{Number{\rm{ }}of{\rm{ }}homozygous{\rm{ }}dominant{\rm{ }}or{\rm{ }}green{\rm{ }}seedlings{\rm{ }}\left( {{C^G}{C^Y}} \right)}}{{Total{\rm{ }}number{\rm{ }}of{\rm{ }}seedlings}}\)

\(\begin{aligned}{l}2pq &= \frac{{111}}{{216}}\\2pq &= 0.51\end{aligned}\)

From the observed frequencies from Day 7, it is given that:

Number of homozygous dominant or yellow seedlings (\({C^Y}{C^Y}\))= 56

Total number of seedlings= 216

The observed genotypic frequency of\({C^Y}{C^Y}\) (\({q^2}\)) is:

\({q^2} = \frac{{Number{\rm{ }}of{\rm{ }}homozygous{\rm{ }}recessive{\rm{ }}or{\rm{ }}yellow{\rm{ }}seedlings{\rm{ }}\left( {{C^Y}{C^Y}} \right)}}{{Total{\rm{ }}number{\rm{ }}of{\rm{ }}seedlings}}\)

\(\begin{aligned}{l}{q^2} &= \frac{{56}}{{216}}\\{q^2} &= 0.259\\{q^2} &= 0.26\end{aligned}\)

Thus, the observed genotypefrequencies of the genotypes\({C^G}{C^G}\),\({C^G}{C^Y}\), and\({C^Y}{C^Y}\)are 0.23, 0.51, and 0.26, respectively.

To calculate: Expected frequencies of genotypes \({C^G}{C^G}\),\({C^G}{C^Y}\), and\({C^Y}{C^Y}\)at day 7 and compare them with the observed genotype frequency.

From the observed frequencies from Day 7, it is given that:

Number of homozygous dominant or green seedlings (\({C^G}{C^G}\))= 49

Total number of seedlings= 216

The allele frequency for\({C^G}\)allele (\(p\)) is:

\(p = \sqrt {\frac{{Number{\rm{ }}of{\rm{ }}homozygous{\rm{ }}dominant{\rm{ }}or{\rm{ }}green{\rm{ }}seedlings{\rm{ }}\left( {{C^G}{C^G}} \right)}}{{Total{\rm{ }}number{\rm{ }}of{\rm{ }}seedlings}}} \)

\(\begin{aligned}{c}p &= \sqrt {\frac{{49}}{{216}}} \\ &= 0.476\\ \simeq 0.48\end{aligned}\)

The expected genotypic frequencyof\({C^G}{C^G}\)(\({p^2}\)) is:

\(\begin{aligned}{l}{p^2} &= 0.48 \times 0.48\\{p^2} &= 0.23\end{aligned}\)

From the observed frequencies from Day 7, it is given that:

Number of homozygous dominant or yellow seedlings (\({C^Y}{C^Y}\))= 56

Total number of seedlings= 216

The allele frequency for\({C^Y}\)allele (\(q\)) is:

\(q = \sqrt {\frac{{Number{\rm{ }}of{\rm{ }}homozygous{\rm{ }}recessive{\rm{ }}or{\rm{ }}yellow{\rm{ }}seedlings{\rm{ }}\left( {{C^Y}{C^Y}} \right)}}{{Total{\rm{ }}number{\rm{ }}of{\rm{ }}seedlings}}} \)

\(\begin{aligned}{c}q &= \sqrt {\frac{{56}}{{216}}} \\ &= 0.509\\ \simeq 0.51\end{aligned}\)

The expected genotypic frequencyof\({C^Y}{C^Y}\)(\({q^2}\)) is:

\(\begin{aligned}{l}{q^2} &= 0.51 \times 0.51\\{q^2} &= 0.26\end{aligned}\)

We have:

\(p = 0.48\)and\(q = 0.51\)

The expected frequency for\({C^G}{C^Y}\)(\(2pq\)) is:

\(\begin{aligned}{l}2pq &= 2 \times 0.48 \times 0.51\\2pq &= 0.489\\2pq &= 0.49\end{aligned}\)

\(2pq = 0.5\)

Thus, the expected frequencies of the genotypes\({C^G}{C^G}\),\({C^G}{C^Y}\), and\({C^Y}{C^Y}\)are 0.23, 0.5, and 0.26, respectively.The observed genotypefrequencies of the genotypes \({C^G}{C^G}\), \({C^G}{C^Y}\), and \({C^Y}{C^Y}\)are 0.23, 0.51, and 0.26, respectively. Therefore, the seedling population is in equilibrium at day 7.

The seedling population is in equilibrium at day seven because each seedling's observed and expected genotype frequencies are similar. It implies that the seedling population is not undergoing evolution.

The observed genotype frequency meets the expected genotype frequency for each seedling. Therefore, at Day 7, there is no evolution, and there are no particular genotypes or a particular allele selected for or against.