Sex chromatin

Sex chromatin - specific chromatin bullock cell nuclei females in humans and other mammals. Are located at the nuclear envelope, on the drugs are usually triangular or oval; size 0,7-1,2 microns (Fig. 1). Sex chromatin formed one of the X-chromosomes of female fetuses and can be found in any human tissues (in the cells of the mucous membranes, skin, blood, bioperegnoy tissue), the Most simple study of sex chromatin is to study it in the cells of epithelial mucous membranes of the oral cavity. Taken putty knife scraping with buccal mucosa is placed on a glass slide, stained with acetoarsenite and analyzed under the microscope 100 light-colored cell nuclei, counting, how many of them contain sex chromatin. In normal conditions it meets, on average, 30-40% of the nuclei in women and is not detected in men (Fig. 2).

sex chromatin

Fig. 1. Kernel containing sex chromatin (scraping from a mucous membrane of an oral cavity healthy women).

Fig. 2. The kernel does not contain sex chromatin (scraping from a mucous membrane of an oral cavity healthy men). Fig. 3. Kernel containing double sex chromatin (scraping from a mucous membrane of an oral cavity of the patient trisomy X).

In conditions of a pathology can change the size Taurus sex chromatin, and their number in each core and an average of 100 cores. Sex chromatin study cytological sex determination (for example, when hermaphroditism); to identify chromosomal diseases (syndrome Shereshevsky - Turner, characterized by lack of sex chromatin in women; syndrome of Kleinfelter in which men reveal the sex chromatin; syndrome, trisomy X, where in the kernel instead of the one young bullock sex chromatin reveal two) (Fig. 3); in some pathological processes, especially malignant (in particular, for solution of the issue of hormonal therapy for breast cancer); to characterize the actions of certain drugs (eg, corticosteroids - to change their number of cells containing a sex chromatin), and other
Cm. also Hereditary diseases.