When two independentaly assorting dominant genes interact with each other to produce particular phenotype but when they present alone they did not produce phenotype they are called

Options

A. Complementary gene
B. Supplementary gene
C. Duplicate gene
D. Inhibitory gene

Answer

**Step-by-Step Solution:**

1. **Understanding Gene Interaction**: The question refers to two independently assorting dominant genes that interact to produce a specific phenotype. When these genes are present alone, they do not express the phenotype. This indicates a specific type of genetic interaction.

**Hint**: Think about how genes can work together to influence traits, rather than acting independently.

2. **Mendel’s Laws**: According to Mendel's principles of inheritance, traits are controlled by genes that come in pairs (alleles). Dominant alleles mask the effects of recessive alleles. However, later research showed that multiple genes can influence a single trait.

**Hint**: Recall Mendel's experiments and how he described the inheritance of traits through dominant and recessive alleles.

3. **Identifying the Interaction**: The interaction described in the question is one where two dominant genes must be present together to produce a phenotype. This type of interaction is known as "complementary gene interaction."

**Hint**: Consider examples where the presence of multiple genes is necessary for a trait to be expressed.

4. **Example of Complementary Genes**: A classic example is found in the flower color of the sweet pea plant (Latyrus odoratus). The presence of both dominant alleles (C and P) is necessary for the expression of purple flowers. If either gene is absent or recessive, the flowers will be white.

**Hint**: Look for real-life examples in plants or animals where two genes interact to produce a specific trait.

5. **Phenotypic Ratio**: In the case of complementary genes, the phenotypic ratio observed is 9:7, where 9 represents the purple flowers (when both dominant alleles are present) and 7 represents the white flowers (when at least one allele is recessive).

**Hint**: Think about how to calculate ratios in genetic crosses and how they reflect the underlying genetic interactions.

6. **Conclusion**: Therefore, the correct answer to the question is that the two independently assorting dominant genes that interact to produce a specific phenotype, but do not produce it alone, are referred to as "complementary genes."

**Hint**: Summarize the key points about complementary genes and their role in genetic inheritance.

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