In basic genetics, which statement best describes the relationship between genotype and phenotype?

• A. Genotype and phenotype are always identical because each allele produces one unique trait regardless of environment.
• B. Genotype is an organism’s allele combination, and phenotype is the observable traits produced by the genotype in a given environment.
• C. Phenotype is determined only by the environment and is independent of genotype.
• D. Genotype refers to observable traits, while phenotype refers to the alleles an organism carries.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the definitions of genotype and phenotype. 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: Recognize that phenotype is the observable physical or biochemical characteristics of an organism, which result from the interaction of the genotype with the environment.
3. Step 3: Note that genotype alone does not always determine phenotype because environmental factors can influence how genes are expressed.
4. Step 4: Evaluate the given statements by comparing them to these definitions: genotype is the allele combination, and phenotype is the trait expression influenced by both genotype and environment.
5. Step 5: Conclude that the correct description is that genotype is an organism’s allele combination, and phenotype is the observable traits produced by the genotype in a given environment.