In genetics, the phenomenon where the expression of one gene is masked or modified by the expression of another non-allelic gene is called: MCQ with Answer and Explanation

In genetics, the phenomenon where the expression of one gene is masked or modified by the expression of another non-allelic gene is called:
A. Penetrance
B. Epistasis
C. Pleiotropy
D. Linkage
Answer: Option B
Solution (By JKExamLibrary)
Epistasis is a form of gene interaction where the expression of one gene (the epistatic gene) masks, suppresses, or modifies the expression of another non-allelic gene (the hypostatic gene). This alters the expected Mendelian dihybrid ratio (9:3:3:1) into modified ratios like 9:7 (complementary), 9:3:4 (recessive epistasis), or 12:3:1 (dominant epistasis). Pleiotropy is one gene affecting multiple traits, and linkage is genes being on the same chromosome.

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Practice More Biology Questions

Question #1
Consider the following statements about DNA fingerprinting:
1. It uses VNTRs (variable number tandem repeats).
2. It can be used in paternity testing.
3. It requires amplification by PCR.
Which of the above is/are correct?
A. 2 and 3 only
B. 1, 2, and 3
C. 1 and 2 only
D. 1 and 3 only

Correct Answer: Option B


Explanation:
DNA fingerprinting analyzes VNTRs, often amplified by PCR, and is used in forensics and paternity. All three are correct.

This question belongs to: Science Biology
Question #2
The transfer of pollen grains from the anther of one plant to the stigma of a genetically different plant is known as:
A. Geitonogamy
B. Xenogamy
C. Autogamy
D. Cleistogamy

Correct Answer: Option B


Explanation:
Xenogamy is the type of cross-pollination where pollen grains are transferred from the anther of one plant to the stigma of a genetically different plant. This promotes genetic diversity. Autogamy is self-pollination within the same flower. Geitonogamy is the transfer of pollen between different flowers on the same plant (functionally cross-pollination but genetically self-pollination). Cleistogamy is closed, self-pollinating flowers.

This question belongs to: Science Biology
Question #3
Consider statements about ecology: 1. A food chain shows the flow of energy. 2. A food web shows interconnected food chains. 3. Decomposers are the primary producers. Which are correct?
A. 1 and 3 only
B. 2 and 3 only
C. 1 and 2 only
D. 1, 2 and 3

Correct Answer: Option C


Explanation:
A food chain is a linear sequence showing the transfer of energy and matter from one organism to another through consumption. A food web is a complex, interconnected network of multiple food chains, representing the realistic feeding relationships in an ecosystem. Decomposers (bacteria and fungi) are saprotrophs that break down dead organic matter; primary producers are autotrophs (plants, algae) that synthesize their own food. Thus, statements 1 and 2 are correct.

This question belongs to: Science Biology