Question

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 50/100 B 84/100 C 50/200 D 134/200 E 100/200

Answer 1

The correct answer is optionD 134/200.

The frequency of the dominant allele can be calculated by the summation of the frequency of the homozygous individual frequency that has  dominant allele  and half of the heterozygous individuals, as half of the heterozygotes have dominant allele.

The frequency is no of individual of desired trait divided by total number of individual.

The calculation is shown below:$frequency of dominant allele=frequency of dominant individual+\frac{1}{2} frequency of heterozygotes\\frequency of dominant allele=\frac{50}{100} +\frac{1}{2} (\frac{34}{100} )\\frequency of dominant allele=\frac{50}{100} +\frac{34}{200} \\frequency of dominant allele=\frac{2(50)+34}{200}\\ frequency of dominant allele=\frac{134}{200}$

Answer 2

The final frequency of dominant alleles is then given by the expression 134/200