Question

Which of the following statements about dominant traits is correct? group of answer choices

O they increase in frequency over evolutionary time.
O they are observed more frequently than recessive traits.
O they are observed one-quarter as frequently as heterozygous traits.
O they are observed less frequently than recessive traits.
O none of the above is correct.

Answer 1

Dominant traits are observed more frequently than recessive traits because a single copy of the dominant allele is sufficient for the trait to appear in the phenotype. The answer is option B.

Step-by-step explanation:

Dominant traits are observed in the phenotype of an individual when at least one dominant allele (the variant form of a gene) is present. Thus, dominant traits are observed more frequently than recessive traits because a single dominant allele is enough to express the trait, whereas recessive traits require two copies of the recessive allele to be visible in the phenotype. The correct statement about dominant traits is that they are observed more frequently than recessive traits.

As described by Gregor Mendel's principles, the phenotype reflects the dominant trait when the genotype is either homozygous dominant ('AA') or heterozygous ('Aa'). In a typical Mendelian cross, when heterozygous offspring ('Aa') are self-crossed, the resulting F2 generation will reflect a 3:1 phenotypic ratio of dominant to recessive characteristics, which does not necessarily mean that dominant traits increase in frequency over evolutionary time.