Answer: A gene is moved near heterochromatin and silenced in some cells but not others (mosaic phenotype).
- A A gene is overexpressed due to amplification of its nearby promoter region in most cases under typical conditions
- B A gene is moved near heterochromatin and silenced in some cells but not others (mosaic phenotype)
- C Every gene across the entire genome becomes uniformly silenced all at once according to standard textbooks
- D Chromosome inversion mainly disrupts ribosomal RNA gene clusters specifically in general practice
Correct answer: B. A gene is moved near heterochromatin and silenced in some cells but not others (mosaic phenotype)
Explanation: Position effect variegation (PEV): gene relocated near heterochromatin by rearrangement. Heterochromatin spreading silences gene variably, producing mosaic phenotype (e.g., eye color mosaicism in Drosophila white gene).
Punnett square for a monohybrid cross between two heterozygous (Tt) parents, showing the 3:1 phenotypic ratio predicted by Mendel's Law of Segregation.
Concept context
Mendel's laws, inheritance patterns, DNA structure, and molecular biology. Core of NEET biology.
Read the full Principles of Inheritance and Variation notes →