Select the correct answer.

In a particular species of frogs, black spots are a dominant trait and their absence is a recessive trait. In a population of frogs, 50 are homozygous for the dominant trait, 34 are heterozygous dominant, and 16 show the recessive trait. Which expression is the correct way to calculate the frequency of the dominant allele?

A. [tex]\frac{50}{100}[/tex]
B. [tex]\frac{34}{100}[/tex]
C. [tex]\frac{50}{200}[/tex]
D. [tex]\frac{14}{200}[/tex]
E. [tex]\frac{100}{200}[/tex]



Answer :

Let's go through the information given step by step and how to calculate the frequency of the dominant allele in the population.

1. Total Number of Frogs:
- Homosexual dominant: 50 frogs.
- Heterozygous dominant: 34 frogs.
- Recessive trait: 16 frogs.
- Therefore, the total number of frogs is [tex]\(50 + 34 + 16 = 100\)[/tex] frogs.

2. Total Number of Alleles:
Since each frog has two alleles, the total number of alleles in the population is [tex]\(2 \times 100 = 200\)[/tex] alleles.

3. Number of Dominant Alleles:
- Homozygous dominant frogs contribute 2 dominant alleles each: [tex]\(50 \times 2 = 100\)[/tex] dominant alleles.
- Heterozygous dominant frogs contribute 1 dominant allele each: [tex]\(34 \times 1 = 34\)[/tex] dominant alleles.
- Frogs with the recessive trait contribute 0 dominant alleles: [tex]\(16 \times 0 = 0\)[/tex] dominant alleles.
- Thus, the total number of dominant alleles in the population is [tex]\(100 + 34 + 0 = 134\)[/tex].

4. Frequency of the Dominant Allele:
To calculate the frequency of the dominant allele, we use the formula:

[tex]\[ \text{Frequency of the dominant allele} = \frac{\text{Total number of dominant alleles}}{\text{Total number of alleles}} \][/tex]

Using the numbers we calculated:

[tex]\[ \text{Frequency of the dominant allele} = \frac{134}{200} = 0.67 \][/tex]

Given these calculations, the correct way to express this calculation from the given options is:

E. [tex]\(\frac{100}{200}\)[/tex]