Answer: Random inactivation of one X in each somatic cell (forming Barr body), creating cellular mosaicism.
- A Largely permanent silencing of both X chromosomes occurring within most cell as generally observed
- B Random inactivation of one X in each somatic cell (forming Barr body), creating cellular mosaicism
- C Consistent inactivation of mainly the maternally inherited X chromosome each time in typical laboratory settings
- D Inactivation of both X chromosomes occurring specifically within male individuals under usual circumstances
Correct answer: B. Random inactivation of one X in each somatic cell (forming Barr body), creating cellular mosaicism
Explanation: Lyon hypothesis: one X is randomly inactivated per female somatic cell, forming a Barr body (inactive X condensed). Each cell expresses either maternal or paternal X alleles.
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 →