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Which of the following is always true of a mutation that produces a dominant allele? A - HSC - SSCE Biology - Question 11 - 2019 - Paper 1
Question 11
Which of the following is always true of a mutation that produces a dominant allele? A. It will be lethal in a population. B. It will be expressed in heterozygous ... show full transcript
Worked Solution & Example Answer:Which of the following is always true of a mutation that produces a dominant allele? A - HSC - SSCE Biology - Question 11 - 2019 - Paper 1
Step 1
B. It will be expressed in heterozygous individuals.
Answer
A dominant allele is defined as an allele that expresses its phenotype in both homozygous and heterozygous states. Therefore, option B is accurate because a dominant allele will always be expressed in heterozygous individuals (e.g., if the genotype is Aa, where A is the dominant allele, the phenotype will exhibit the traits associated with A).
In contrast, the other options can be discussed as follows:
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A. It will be lethal in a population: Not all dominant alleles are lethal; many can be neutral or beneficial.
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C. It will only be expressed in homozygous individuals: This is not true, as dominant alleles are expressed in both homozygous (AA) and heterozygous (Aa) forms.
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D. It will spread more quickly through the population than a recessive allele: While dominant traits may spread more quickly due to their expression in heterozygotes, this is not universally true as many factors affect allele frequency in a population.