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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{84}{100}[/tex]
C. [tex]\frac{50}{200}[/tex]
D. [tex]\frac{134}{200}[/tex]
E. [tex]\frac{100}{200}[/tex]



Answer :

GinnyAnswer
To determine the correct calculation for the frequency of the dominant allele in the population, let's break down the details step-by-step:

1. Define the Population Counts:
- Homozygous dominant frogs (BB): 50
- Heterozygous dominant frogs (Bb): 34
- Recessive trait frogs (bb): 16

2. Calculate the Total Number of Frogs:
- Total frogs [tex]\( = 50 (BB) + 34 (Bb) + 16 (bb) = 100 \)[/tex]

3. Determine the Number of Alleles:
Since each frog carries two alleles:
- Total alleles in the population [tex]\( = 2 \times \text{total number of frogs} = 2 \times 100 = 200 \)[/tex]

4. Calculate the Number of Dominant Alleles:
- Each BB frog has 2 dominant alleles, so BB contributes [tex]\( 2 \times 50 = 100 \)[/tex] dominant alleles.
- Each Bb frog has 1 dominant allele and 1 recessive allele, so Bb contributes [tex]\( 1 \times 34 = 34 \)[/tex] dominant alleles.
- bb frogs do not contribute any dominant alleles.

So, the total number of dominant alleles [tex]\( = 100 (\text{from BB}) + 34 (\text{from Bb}) = 134 \)[/tex]

5. Calculate the Frequency of the Dominant Allele:
The frequency of the dominant allele is the number of dominant alleles divided by the total number of alleles:
[tex]\[ \text{Frequency of dominant allele} = \frac{\text{number of dominant alleles}}{\text{total number of alleles}} = \frac{134}{200} \][/tex]

Looking at the provided options, the correct expression to calculate the frequency of the dominant allele is:

D. [tex]\( \frac{134}{200} \)[/tex]

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