In fundamental genetics, how do the terms genotype and phenotype relate to each other?

• A. Genotype is an organism’s allele combination, and phenotype is the observable trait produced by the genotype (often influenced by the environment).
• B. Genotype describes environmental effects on traits, while phenotype describes inherited DNA sequence only.
• C. Genotype and phenotype both refer only to the observable traits of an organism.
• D. Genotype refers to observable traits, while phenotype refers to the underlying allele combination.

Answer: (A)

Verified step by step guidance

1. Step 1: Define genotype as the genetic makeup of an organism, specifically the combination of alleles (versions of a gene) that an organism carries.
2. Step 2: Define phenotype as the observable physical or biochemical characteristics of an organism, which result from the interaction of its genotype with the environment.
3. Step 3: Explain that the genotype provides the genetic instructions, while the phenotype is the expression of those instructions, which can be influenced by environmental factors.
4. Step 4: Clarify that genotype is not directly observable without genetic testing, whereas phenotype is what we can see or measure, such as eye color, height, or blood type.
5. Step 5: Conclude that the correct relationship is: genotype is the allele combination, and phenotype is the observable trait produced by the genotype, often influenced by the environment.