"Sexing" deoxyribonucleic acid (DNA) on DNA fingerprint gel: an internal control for DNA fingerprint evidence

Deoxyribonucleic acid (DNA) isolated from male and female fresh blood samples was processed exactly as for routine DNA fingerprint analysis; that is, the DNA was digested with particular restriction endonucleases and fractionated by agarose gel electrophoresis. Ultraviolet (UV) visualization of ethidium-bromide (EtBr)-stained gels revealed a sex-specific banding pattern, which depended only on the restriction enzyme used. By means of this test, which is based on direct detection of particular sex-specific restriction fragments in human DNA digests, the authors succeeded in determining the sex of DNA obtained from biological specimens recovered as criminal evidence in rape cases. The data obtained demonstrate that direct sexing of DNA on DNA fingerprint gel appears to be useful as an intermediate control step in DNA fingerprinting analysis used for the purpose of assailant identification.