In genetics, which statement best describes the difference between a genotype and a phenotype?

• A. Genotype is an organism’s genetic makeup (allele combination), while phenotype is the observable traits produced by the genotype and environment.
• B. Genotype and phenotype are identical terms that both mean an organism’s physical appearance.
• C. Genotype refers to the observable traits of an organism, while phenotype refers to its DNA sequence.
• D. Genotype is the set of environmental conditions an organism experiences, while phenotype is the set of alleles it carries.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the definition of genotype. Genotype refers to the genetic makeup of an organism, specifically the combination of alleles it carries for a particular gene or set of genes.
2. Step 2: Understand the definition of phenotype. Phenotype is the observable physical or biochemical characteristics of an organism, which result from the interaction of its genotype with the environment.
3. Step 3: Recognize that genotype is about the DNA sequence or allele combination, which is inherited and fixed, while phenotype is about traits that can be seen or measured, such as height, eye color, or enzyme activity.
4. Step 4: Note that phenotype can be influenced by both genotype and environmental factors, meaning two organisms with the same genotype can have different phenotypes if they experience different environments.
5. Step 5: Use this understanding to evaluate the statements: the correct description is that genotype is the organism's genetic makeup (allele combination), and phenotype is the observable traits produced by the genotype and environment.