A phenocopy occurs when __________.

• A. environmental influences mimic the effect of a gene
• B. individual has an exact copy of another's genotype
• C. two individuals have exactly the same genetic composition
• D. an individual carries two identical alleles

Answer: (A)

Verified step by step guidance

1. Understand the concept of a phenocopy: A phenocopy is a phenomenon where an individual's phenotype is altered due to environmental factors, making it resemble the phenotype that would be produced by a specific genotype.
2. Differentiate between genetic and environmental influences: Genetic influences are determined by the individual's DNA, while environmental influences are external factors that can affect the phenotype.
3. Identify the key characteristic of a phenocopy: It is important to note that a phenocopy does not involve changes to the individual's genotype; rather, it is the environment that causes the phenotype to mimic that of a genetic condition.
4. Consider examples of phenocopies: For instance, certain environmental factors like diet, temperature, or exposure to chemicals can lead to phenotypic changes that resemble genetic conditions.
5. Review the options provided: The correct answer is the one that describes environmental influences mimicking the effect of a gene, as this aligns with the definition of a phenocopy.