Question

In a species of fish, fin shape is controlled by a single gene that has only two alleles. In a generation of 185 fish, the frequency of the recessive allele is 0.25. After six generations, the recessive allele frequency in a population of 230 fish is 0.43. Which of the following does this most likely indicate about the dominant and recessive alleles?
The dominant allele is more advantageous than the recessive allele because it produces larger populations.
The dominant allele will disappear entirely as the recessive allele increases in frequency.
The recessive allele is easier to transmit than the dominant allele during reproduction.
The recessive allele produces a phenotype that is better able to survive and reproduce than the dominant phenotype.

Answer 1

The correct answer is: The recessive allele produces a phenotype that is better able to survive and reproduce than the dominant phenotype.

Natural selection (adaptation mechanism), gene flow, and mutation combine to change allele frequencies across generations. Natural selection tends to increase in frequency beneficial alleles, while it tends to decrease in frequency deleterious alleles.