Masking of Non-Allelic Gene Expression
When one gene masks the expression of another non-allelic gene, it is known as:
- Dominance
- Epistasis — Correct Answer
- Pleiotropy
- Linkage
Explanation:
Correct Answer: Epistasis
Epistasis is an intergenic (non-allelic) interaction where one gene masks or suppresses the phenotypic expression of a different gene at a separate locus. The masking gene is called the epistatic gene; the masked gene is called the hypostatic gene.
Types of Epistasis — F₂ Phenotypic Ratios
| Type | F₂ Ratio |
|---|---|
| Dominant epistasis | 12 : 3 : 1 |
| Recessive epistasis / Supplementary gene action | 9 : 3 : 4 |
| Complementary gene action | 9 : 7 |
| Duplicate gene action | 15 : 1 |
| Inhibitory gene action | 13 : 3 |
| Collaborative gene action | 9 : 3 : 3 : 1 |
Why Other Options Are Wrong
- Dominance: Interaction between alleles at the same locus — allelic (intragenic) interaction.
- Pleiotropy: One gene affects multiple traits — not masking of another gene.
- Linkage: Genes located on the same chromosome that tend to be inherited together — no masking involved.
📚 About this Topic — Animal Genetics & Breeding
This multiple choice question is from Animal Genetics & Breeding, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Genetics & Breeding to strengthen your preparation.
