Question

In soybeans, GG seedlings have green leaves, Gg seedlings have green-yellow leaves, and 88 seedlings have yellow leaves. In a population of soybeans, you observe: 49 seedlings with green leaves 111 seedlings with green-yellow leaves 56 seedlings with yellow leaves For each of the following questions, enter your answer to three decimal places (for example, enter 0.113 as an answer). What is the frequency of the Gallele (p)? What is the frequency of the gallele (q)? If the population is in Hardy-Weinberg equilibrium, what is the expected frequency of the GG genotype? what is the expected frequency of the Gg genotype? what is the expected frequency of the Gg genotype?

Answer 1

Number of soybeans that have GG seedlings (Green leaves) = 49

Number of soybeans that have Gg seedlings (Green - Yellow leaves) = 111

Number of soybeans that have gg seedlings (Yellow leaves) = 56

Frequency of each allele = Number of each allele / Total number of alleles

Frequency of G allele (p) = No. of GG soybeans x 2 + No. of Gg soybeans / Total number of soybeans x 2

(soybeans which have genotype GG have 2 copies of G allele, Soybeans with Gg have only one copy of G allele. And total number of alleles will be double the number of soybeans)

So, Frequency of G allele (p) = No. of G allele / Total no. of alleles

= (49 x 2) + 111 / (49+111+56) x 2

= 98 + 111 / 216 x 2 = 209 / 432 = 0.484

Frequency of g allele = No. of g allele/ Total no. of allele

(ggSoybeans have 2 copies of g allele and Gg soybeans have one copy of g allele)

So frequency of g allele (q) = ( 56x 2) + 111 / 432 = (112 +111) / 432 = 223 / 432 = 0.516

If the population is in Hardy- Weinberg equilibrium, it will have the following genotype frequencies.

GG genotype = p2

gg genotype = q2

Gg genotype = 2 pq

so, Expected frequency of GG genotype = 0.484 x 0.484 = 0.234

Expected frequency of gg genotype = 0.516 x 0.516 = 0.266

Expected frequency of Gg genotype = 2 x 0.484 x 0.516 = 0.499