Examkin

Question

Difficulty: MediumGenetics and Heredity

An organism that displays a dominant phenotype must possess a homozygous genotype for that specific trait.

Answer: Answer

Answer

False. An organism exhibiting a dominant phenotype can possess either a homozygous dominant or a heterozygous genotype.
In complete dominance, a dominant allele masks the expression of a recessive allele. An individual can express the dominant phenotype through two distinct genotypes: homozygous dominant (having two copies of the dominant allele) or heterozygous (having one dominant and one recessive allele). Thus, displaying the dominant phenotype does not require a homozygous genotype.

Step-by-Step Solution

1
Distinguish between genotype and phenotype under Mendelian inheritance.
Genotype represents the specific combination of alleles (AAAA, AaAa, or aaaa), whereas phenotype represents the observable physical characteristic.
To establish the relationship between genetic makeup and outward physical expression.
2
Identify which genotypes yield a dominant phenotype in a complete dominance system.
Both homozygous dominant (AAAA) and heterozygous (AaAa) genotypes result in the dominant phenotype because the dominant allele masks the recessive allele.
To evaluate whether a homozygous genotype is strictly required to express the dominant phenotype.
3
Assess the validity of the statement.
Because heterozygous individuals (AaAa) also express the dominant phenotype, having a dominant phenotype does not guarantee a homozygous genotype.
To determine the final true/false evaluation of the statement.

Key Concept

Dominant and Recessive Alleles in Genotype versus Phenotype Expression
Estimated Time:45s
Rate this question

Topics

Genetics and Heredity

More questions from this topic