Sexual Chromatin: Structure, Functions and Significance in Medical Practice

Аннотация

The concept of sex chromatin plays an important role in genetics, cytology and medical practice. Sex chromatin is a condensed inactive X chromosome in the nucleus of somatic cells in female mammals. This phenomenon is explained by a dosage compensation mechanism that ensures equal amounts of X-sex chromosome gene products in males and females. Sex chromatin is an important object of cytogenetic studies, allowing the diagnosis of disturbances in the number of X-sex chromosomes and the differential diagnosis of hereditary chromosomal diseases. Keywords: Sex chromatin, Barr bodies, X-sex chromosome, genotype, trisomy, Klinefelter syndrome, Turner syndrome, amniotic fluid. is inactive, which is manifested in its stronger Introduction: Sexual chromatin was first described in spiralization and densification. In the interphase 1949 by Canadian scientist Murray Barr and his nucleus, this spiralized X chromosome is visible as X- colleague E. Bertram while studying the cells of the chromatin. Y-chromatin in humans and some primates nervous tissue of cats. They found a dense colored body has a large heterochromatin region that produces near the nuclear membrane, which was present only in intense fluorescence. Thus, a technically simple study females. Later, it was found that this formation of the interphase nucleus makes it possible to judge the corresponds to the inactivated X-sex chromosome. state of the sex chromosome system. X-chromatin is Further studies confirmed the presence of Barr bodies more or less often found in women in the nuclei of cells in other mammals and explained the mechanism of X- of all tissues (for example, in the epithelial cells of the sexual inactivation. oral mucosa in 15-60% of the nuclei). The number of Sex chromatin, a dense, staining body found in the non- nuclei with X-chromatin depends on the intensity of cell dividing nuclei of cells in heterogeneous (having X and reproduction in a given tissue and on the hormonal Y sex chromosomes) animals and humans. Sexual state of the body. A change in the amount of sex chromatin is divided into X-chromatin, or Barr's body, chromatin indicates a change in the number of sex and Y-chromatin (discovered in 1970 by Swedish chromosomes, which is detected by the cytogenetic scientists T. Kaspersky and L. Tsekh). X-chromatin is a method of human genetics. body that is intensely stained with basic dyes (0.7—1.2 The nature and formation of sex chromatin was first microns), more often adjacent to the nuclear envelope explained by the English geneticist Mary Lyon in 1961. and having a triangular semilunar or rounded shape. Y- When comparing the female (XX) and male (XY) sex chromatin is much smaller in size and is detected when chromosomes, it was found that the genes in the X the nucleus is stained with fluorochromes (akrikhin, chromosome can show all the signs on their own akrikhiniprit) and examined in ultraviolet light. In without forming XX. For example, men (XY) have one X female individuals (type XX), one of the X chromosomes chromosome, but it alone carries all the information. American Journal Of Biomedical Science & Pharmaceutical Innovation 19 https://theusajournals.com/index.php/ajbspi American Journal of Applied Science and Technology (ISSN: 2771-2745) Based on this, Lyon explained the formation of sex presence or absence of sexual chromatin, the child's chromatin. In women, one of the X-sex chromosomes proper sex is determined and various measures are is inactive, it is formed at the stage of the interphase of taken to form a natural medical gender. DNA division from an inactive strongly twisted and 4. In transplantation. spiralized chromosome, and it also forms a small body 5. In the forensic medical examination. Using the clearly visible under the microscope. And the second X method of determining sex chromatin, it is possible to chromosome is active, it carries genes that manifest determine the sex of a person. their functions, and the DNA is in an unspiralized state, in the form of a thin long strand. For this reason, this CONCLUSION chromosome is not visible under a microscope. Sex chromatin is an important object of study in the The transition to the inactive state of one of the X field of human genetics and medicine, since the chromosomes in the female body is observed randomly method of determining sex chromatin allows us to in the early embryonic period. However, the property obtain valuable data on sex chromosomes and their of DNA division in an inactive chromosome remains. In behavior in cells. The use of sex chromatin research the female body, one X chromosome is derived from methods is widely used in the diagnosis of various the father, the other from the mother. The human chromosomal diseases, as well as in various manifestation of symptoms depends on the transition areas of medical practice. of one of the sex chromosomes to an inactive state. If REFERENCES the chromosome received from the mother contains К.Н. Нишанбаев, П. Р. Ал