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Multiple Choice
What is the difference between a dominant and a recessive trait?
A
A dominant trait is expressed only in homozygous individuals, while a recessive trait is expressed in heterozygous individuals.
B
A dominant trait is expressed when at least one copy of the allele is present, while a recessive trait is expressed only when two copies are present.
C
A dominant trait is expressed only when two copies of the allele are present, while a recessive trait is expressed with just one copy.
D
A dominant trait is always expressed in the phenotype, while a recessive trait is never expressed.
Verified step by step guidance
1
Understand the basic definitions: A dominant trait is one that is expressed in the phenotype even if only one copy of the allele is present. A recessive trait, on the other hand, is only expressed in the phenotype when two copies of the allele are present.
Consider the genetic makeup: In genetics, alleles are different forms of a gene. An individual inherits two alleles for each gene, one from each parent. These alleles can be either dominant or recessive.
Analyze the expression of traits: A dominant allele will mask the presence of a recessive allele in a heterozygous individual (one dominant and one recessive allele), resulting in the dominant trait being expressed.
Examine homozygous and heterozygous conditions: A recessive trait is expressed only when an individual is homozygous for the recessive allele, meaning they have two copies of the recessive allele.
Apply this understanding to the options: The correct statement is that a dominant trait is expressed when at least one copy of the allele is present, while a recessive trait is expressed only when two copies are present.