The study of the Barr body from the (female) smear of Buccal epithelial cells.
- Buccal epithelial cells
- Giemsa stain
- Carnoy’s fixative
- Cover slip
- Microscope, etc.
- Gently rub the inside of the cheek with a flat rounded piece of wood and
transfer the scraping over a clean glass slide.
- Then, made a thin film of cells on the slide and keep them for air-drying.
- Air-dried smear was kept in Carnoy’s fixative for 30–35 minutes.
- Then, the Giemsa stain was poured and allowed to stand for 20–25 minutes.
- After staining, the slide was washed with distilled water to remove the
- Finally, the slide was kept for air-drying and then observed under the
We found that very lightly stained cells are scattered here and there in the
smear. In the cells, violet-Barr bodies are observed inside a pink nucleus. A Barr
body is nothing but an inactivated (heterochromatinized) X chromosome. It was
first observed by Murray Barr in 1949. It is found only in female cells, because
in those 1 X chromosome is enough for metabolic activity. It is absent in male
somatic cells, because there only 1 X chromosome is present, which is in an
The smear or film should be uniform and thin over the glass slide so that the
cells will not overlap each other.