How does sex chromatin help identify sex?
Identification of sex chromatin The sex chromatin, also known as the “Barr body,” is formed during embryonic life. X-chromosome inactivation and appearance of the sex chromatin occur at the 4–8 cell stage. This method depends upon identification of the dark staining body adjacent to the nuclear membrane.
What is sex chromatin staining?
The sex chromatin is deep blue-violet and sharply contrasted against the lightly colored particulate chromatin of the nucleus. Cytoplasm remains unstained but fibrin and related structures show metachromasia. Chromosomes are well demonstrated if present.
Where is the sex chromatin in a man?
A dense particle, the size of sex chromatin, is found lying adjacent to the nuclear membrane in 46% of living female cells. This particle is identical with the sex chromatin seen in the same cells after Feulgen or thionin staining.
What is buccal smear test used for?
Overview. A buccal smear is a test where cells are taken from the cheek. Cells are collected by scraping the cheek with a cotton swab. The cells can be used for genetic testing, as well as evaluated for the presence of Barr bodies (a mass seen in a normal female sex chromosome).
Can you have an XXY chromosome?
Males have an X and a Y sex chromosome (XY). Klinefelter syndrome can be caused by: One extra copy of the X chromosome in each cell (XXY), the most common cause. An extra X chromosome in some of the cells (mosaic Klinefelter syndrome), with fewer symptoms.
How is buccal smear done?
A buccal smear is a test where cells are taken from the cheek. Cells are collected by scraping the cheek with a cotton swab. The cells can be used for genetic testing, as well as evaluated for the presence of Barr bodies (a mass seen in a normal female sex chromosome).
How long do buccal swabs last?
6 months
As long as cheek swabs are stored in the paper envelopes provided in the buccal swab kit (not in plastic) and are kept in a cool, dry place, samples remain viable for up to 6 months.
Why do males not have Barr bodies?
Since women have two X chromosomes, one being inactivated, a single Barr Body is present in female mammal cells while males typically have no Barr Body present since they have only one X chromosome.