Type O blood donors ("universal donors") are the most useful, because their blood can be transfused into patients with blood type O, A, B, or AB. The allele frequency of the O allele in the U.S. population is 2/3. The U.S. population is in Hardy-Weinberg equilibrium for blood type. What is the frequency of people with the type O blood type in the U.S. population?
A. 1/3
B. 1/4
C. 1/9
D. 2/9
E. 4/9

Respuesta :

Answer:

option E. [tex]\frac{4}{9}[/tex]

Explanation:

According to the question,

Allele frequency of the 'O' allele in the US population ,p = [tex]\frac{2}{3}[/tex]

Therefore, frequency for the rest of the patients, q = 1 - p =  [tex]1 - \frac{2}{3} = \frac{1}{3}[/tex]

Hardy- Weinberg equilibrium  condition states that in absence of the factors that can cause disturbance, the amount or extent of variation in genes in a population will not vary (constant) throughout the generations.

Therefore,

p + q = 1

In accordance to Hardy- Weinberg equilibrium  eqn:

[tex]p^{2} + 2pq + q^{2} = 1[/tex]                            (1)

where,

[tex]p^{2}[/tex] = homozygous dominant

[tex]q^{2}[/tex] = homozygous recessive

2pq = heterozygous

Using eqn (1)

[tex](\frac{2}{3})^{2} + 2(\frac{2}{3})(\frac{1}{3}) + (\frac{1}{3})^{2} = 1[/tex]

[tex]\frac{4}{9} + \frac{4}{9} + \frac{1}{9} = 1[/tex]

Therefore, the frequency of people with blood type 'O' in the U.S. population is  [tex]p^{2} = \frac{4}{9}[/tex]