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Difficulty: MediumGenetics and Heredity

In genetics, which statement correctly describes the function of a dominant allele?

  1. A
    It must be inherited from both parents to be expressed in an organism's phenotype.
  2. B
    It is always the most common allele found within a natural population.
  3. It masks the phenotypic expression of a recessive allele in a heterozygous individual.Answer
  4. D
    It consistently provides a biological survival advantage over any recessive allele.

Answer

The dominant allele masks the phenotypic expression of a recessive allele in a heterozygous individual.
In genetics, a dominant allele produces its characteristic phenotype whether an individual carries two copies (homozygous dominant) or only one copy paired with a recessive allele (heterozygous).

Step-by-Step Solution

1
Define genetic dominance
Dominance describes the relationship between two alleles where one allele masks the observable effect of the other in a heterozygous genotype.
Understanding the precise biological definition distinguishes dominance from population frequency or fitness.
2
Evaluate the mechanism of expression
An individual with one dominant and one recessive allele (AaAa) displays the dominant phenotype.
A single copy of a dominant allele is sufficient for its physical trait to appear.

Key Concept

Dominant and Recessive Alleles
Estimated Time:45s
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Topics

Genetics and Heredity

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