Question

Answer the following questions
At the Hardy Weinberg equation. For each question
assume that just two alleles of a gene exist in the population. A1 codes for purple leaves, has A frequency of 0.7 and is dominant. A2, codes for white leaves, and has a frequency of 0.3.

14. a) If p is the frequency of A1 and q is the frequency of A2, what equation describes the
relationship between p and q? Explain your answer. (2 points)

b) Describe the frequencies of alleles A1, and A2 in the population using both decimals and
percents. (1 point)

Answer 1

Answer:

a) The equation describes the  relationship between p and q is p + q = 1 for allelic frequencies

b) The frequencies of alleles A1 in decimals is 0.7 and in percents is 70%.

The frequencies of alleles A2 in decimals is 0.3 and in percents is 30%.

Explanation:

According to Hardy-Weinberg, the allelic frequencies in a locus are represented as p and q, referring to the allelic dominant or recessive forms. The genotypic frequencies after one generation are p² (Homozygous dominant), 2pq (Heterozygous), q² (Homozygous recessive). Populations in H-W equilibrium will get the same allelic frequencies generation after generation. The sum of these allelic frequencies equals 1, this is p + q = 1.

In the same way, the sum of genotypic frequencies equals 1, this is

p2 + 2pq + q2 = 1

Being

• p the dominant allelic frequency,

• q the recessive allelic frequency,

• p²the homozygous dominant genotypic frequency

• q² the homozygous recessive genotypic frequency

• 2pq the heterozygous genotypic frequency

In the exposed example,

• A1 codes for purple leaves, has a frequency of 0.7 and is dominant.

• A2 codes for white leaves, has a frequency of 0.3 and is recessive.

According to this equation: p + q = 1.

                                             0.7 + 0.3 = 1

A1A1= p²= 0.7² = 0.49

A2A2= q² = 0.3² = 0.09

A1A2 = 2pq = 2 x 0.7 x 0.3 = 0.42

According to this equation: p² + 2pq + q² = 1

                                             0.49 + 0.42 + 0.09 = 1

• The frequencies of alleles A1 in decimals is 0.7 and in percents is 70%.

• The frequencies of alleles A2 in decimals is 0.3 and in percents is 30%.