Chromatin found only in female cells; it usually occurs as a small object (Barr body) near the nucleus or as a drumstick shaped appendage to the nucleus of some white cells. The presence or absence of sex chromatin is the basis of sex determination before birth through examination of cells obtained by amniocentesis.
A test done on a tissue sample obtained from the membranes that line the inside of the cheek to evaluate the patient for evidence of abnormal sexual development such as ambiguous genitalia, and sexual status in general.
Chromatin found only in female cells and believed to represent a single X chromosome in a nondividing cell. It can be used to discover the sex of a baby before birth by examination of cells obtained by amniocentesis. There are two main kinds: (1) the Barr body, a small object that stains with basic dyes, found on the edge of the nucleus just inside the nuclear membrane; (2) a drumstick like appendage to the nucleus in neutrophils (a type of white blood cell).