Medico-legal importance of sex chromatin - Sex Determination

Sex chromatin test

• In females, any nucleated cells as the epithelial cells of buccal mucous membrane and hair root cells and tooth pulp show one or more tiny nodes of chromatin attached to the inner surface of the nuclear membrane (Barr bodies). In polymorphs, there is Davidson's body as a bud of chromatin on nucleus, it takes drum stick appearance.
• In males, chromosomal examination for Y chromosome by quinacrine dye.

Sex chromatin test is a good helpful aid in the identification of sex in forensic medicine which assists in resolving many medico-legal problems either in living or dead persons.

1. Determination of the actual sex in cases of change of sex from male to female or the reverse, or in cases of intersexuality such as hermaphrodites,

2. Determination of sex from human specimens found at the scene of a crime or on a weapon.

3. In case of confusion about appropriate sex assignment to babies with ambiguous external genitalia and as a result, poor assignment of sex may lead to medico-legal problems.

4. Identification of parts of dead bodies. It was shown that sex chromatin bodies remain visible for sometime after death, but the length of time is variable depending on the type of tissue and organs examined and on the environmental conditions under which the tissues were left.

Gonadal biopsy: This is conclusive

DNA examination and X-ray to certain bones:

Identification of sex in advanced decomposed or mutilated bodies is detected by

• using the polymerase chain reaction (PCR) of the sex chromosome specific locus , X-Y homologous gene Amelogenin

• examination of the bones (skull, sternum and pelvis).
  

Category: Forensic Medicine Notes