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DNA Preparation from Sexual Assault Cases by Selective Degradation of Contaminating DNA from the Victim
Author(s) -
Garvin Alex M.,
Bottinelli Michel,
Gola Mauro,
Conti Ario,
Soldati Gianni
Publication year - 2009
Publication title -
journal of forensic sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.715
H-Index - 96
eISSN - 1556-4029
pISSN - 0022-1198
DOI - 10.1111/j.1556-4029.2009.01180.x
Subject(s) - nuclease , dna , sperm , lysis , sexual assault , centrifugation , deoxyribonuclease i , biology , microbiology and biotechnology , chemistry , biochemistry , genetics , poison control , medicine , base sequence , injury prevention , environmental health
The standard method to purify sperm DNA from vaginal swabs taken from rape victims is to selectively digest the victim’s epithelial cells to solubilize the victim’s DNA, and then separate the soluble DNA from the intact sperm by centrifugation. A different approach to removing the soluble victim’s DNA is to selectively degrade it using a nuclease, DNase I. DNase I reduces the amount of soluble DNA by over 1000‐fold, while having virtually no effect on the sperm DNA remaining in the sperm head and inaccessible to the enzyme. Nuclease inactivation and sperm lysis then yield a soluble, pure male DNA fraction. An aliquot of soluble DNA is removed prior to nuclease addition to provide the victim’s fraction. Vaginal swabs taken at defined time points following consensual sex and taken from rape victims were processed using the nuclease method or the standard method and the nuclease method gave superior short tandem repeat profiles.