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]$\frac{3}{120}$[/tex]
B. [tex]$\frac{4}{4}$[/tex]
C. [tex]$\frac{38}{280}$[/tex]
D. [tex]$\frac{14}{2x}$[/tex]
E. 3



Answer :

Let's analyze the problem step-by-step:

1. Determine the total population of frogs:
- Homozygous dominant (having two dominant alleles): 50
- Heterozygous dominant (having one dominant and one recessive allele): 34
- Recessive trait (having two recessive alleles): 16

The total population is calculated by adding up the three groups:
[tex]\[ 50 + 34 + 16 = 100 \][/tex]

2. Calculate the total number of dominant alleles:
- Homozygous dominant frogs each have 2 dominant alleles. Therefore, the total number of dominant alleles from homozygous dominant frogs is:
[tex]\[ 50 \times 2 = 100 \][/tex]
- Heterozygous dominant frogs each have 1 dominant allele. Therefore, the total number of dominant alleles from heterozygous dominant frogs is:
[tex]\[ 34 \times 1 = 34 \][/tex]

Adding these together, the total number of dominant alleles is:
[tex]\[ 100 + 34 = 134 \][/tex]

3. Calculate the total number of alleles in the population:
Each frog has 2 alleles. Therefore, the total number of alleles in the population is:
[tex]\[ 100 \times 2 = 200 \][/tex]

4. Calculate the frequency of the dominant allele:
The frequency of the dominant allele is given by dividing the number of dominant alleles by the total number of alleles:
[tex]\[ \text{Frequency of dominant allele} = \frac{134}{200} = 0.67 \][/tex]

So, the correct expression to calculate the frequency of the dominant allele is:
[tex]\[ \frac{134}{200} \][/tex]
This is not directly one of the choices listed, but it can be inferred that none of the provided expressions are correct in this context.

``` Given the listed options, it seems the choices do not match the correct formula for the frequency of the dominant allele. Hence, there might be a mistake in the options provided or an error in transcription.