Question

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. $\frac{50}{100}$
b. $\frac{84}{100}$
c. $\frac{80}{200}$
d. $\frac{134}{200}$
e. $\frac{100}{200}$

Explanation:

Step1: Calculate total number of alleles

Total number of frogs \(n = 50 + 34+16=100\). Each frog has \(2\) alleles, so total number of alleles \(N = 100\times2 = 200\)

Step2: Calculate number of dominant alleles

Homozygous dominant frogs (\(AA\)) have \(2\) dominant alleles each. There are \(50\) homozygous dominant frogs, so number of dominant alleles from them is \(50\times2=100\). Heterozygous frogs (\(Aa\)) have \(1\) dominant allele each. There are \(34\) heterozygous frogs, so number of dominant alleles from them is \(34\times1 = 34\). Total number of dominant alleles \(=100 + 34=134\)

Step3: Calculate frequency of dominant allele

Frequency of dominant allele \(=\frac{\text{Number of dominant alleles}}{\text{Total number of alleles}}=\frac{134}{200}\)

Answer:

D. \(\frac{134}{200}\)