Why don't similar genotypes always produce the same phenotype?

• A. Phenotypes are determined solely by random chance, not by genotype.
• B. Genotypes always produce identical phenotypes regardless of conditions.
• C. Only mutations can cause differences in phenotype among similar genotypes.
• D. Environmental factors can influence gene expression, leading to different phenotypes.

Answer: (D)

Verified step by step guidance

1. Understand the relationship between genotype and phenotype: Genotype refers to the genetic makeup of an organism, while phenotype refers to the observable traits or characteristics of that organism.
2. Recognize that gene expression is influenced by environmental factors: Environmental conditions such as temperature, nutrition, light, and stress can affect how genes are expressed, leading to variations in phenotype.
3. Learn about epigenetics: Epigenetic modifications, such as DNA methylation and histone modification, can alter gene expression without changing the underlying DNA sequence, contributing to phenotypic differences.
4. Consider developmental factors: The timing and location of gene expression during development can result in different phenotypes, even among organisms with similar genotypes.
5. Understand that random chance plays a role: Stochastic (random) processes in gene expression can also lead to variability in phenotypes among individuals with similar genotypes.