Sex Typing of Different Human Samples Using X and Y Specific Probes by In-Situ Hybridization.

¹Dalal M El-Kaffash, ²Ragaa T Darwish and ²Mona M Hassan.

Departments of Clinical ¹Pathology, and ²Forensic Medicine & Toxicology, Alexandria University, Faculty of Medicine, Egypt.

Diagnosing the sex of biological evidence can provide important information in a forensic investigation. Many methods for determining the human male sex type have been developed based on the use of chromosome Y-specific sequences. In this study the aim was to test the application of non-radioactive in-situ hybridization technique for sexing human cells. The material used was cells from tissues (soft tissue imprints) and cell sediments from biological fluids randomly collected and blindly tested. The pBamX5 probe for X chromosome and DYZ1 probe for Y chromosome were used for in-situ hybridization. Male metaphase chromosome spreads 46,XY were used as control for the hybridization. For the X chromosome signals, it was possible to detect their expected number in 80% of the cells or more in both sexes. The Y chromosome signals were detected in 75% or more of the male cells, while no Y signal was detected in about 90% of female cells. Therefore, it is possible to use non-radioactive in situ hybridization for sex determination, specially females in biological specimens.