Barr body is found in the following phase of the cell cycle (DNB Pattern)
- The two X-chrmosomes in females dipliod somatic cells exhibit striking morphologic and functional differences:
i. One X-chromosome is in a highly condensed (Heteropyknotic) state in INTERPHASE and is visible as sex chromatin (BARR BODY Q. It completes DNA synthesis later than any other chromosome, and the action of genes located on the precociously condensed segments is suppressed by transcriptional inactivation.
ii. The other X-chromosome, the single X-chromosome in male somatic cells, is in a highly extended (isopyknotic) state during INTERPHASE. It completes DNA replication with most of the complement and is genetically active.
- The discordant behavior of two homologous X-chromosomes in female somatic cells serves as a mechanism of dosage compensation.