DNA Preparation from Sexual Assault Cases by Selective Degradation of Contaminating DNA from the Victim

Garvin, Alex M.; Bottinelli, Michel; Gola, Mauro; Conti, Ario; Soldati, Gianni

doi:10.1111/j.1556-4029.2009.01180.x

Cited by 42 publications

(26 citation statements)

References 17 publications

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“…Our data is consistent with that of other authors [6][7][8]. In clothing, the probability of obtaining a male autosomal genetic profile from single-source is higher, possibly due to a better male:female DNA proportion than that of vaginal swabs.…”

Section: Discussionsupporting

confidence: 95%

Stains of ejaculated pre and post-vasectomy: Purity and sufficient quantity of recovered DNA after 10 years of storage

Mautoni

Astolphi

Mello

et al. 2015

Forensic Science International: Genetics Supplement Series

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Vasectomy is a widely used method of contraception. The absence of spermatozoa in the ejaculate of azoospermic individuals increases the difficulty of extracting DNA for analysis, especially if the biological samples are in the form of spots and stored for years. The aim of this study is to evaluate the possibility of obtaining autosomal and Y-STR profiles from stains containing the ejaculate of individuals pre and post-vasectomy, stored in cotton fabric for a period of 10 years. Samples from 28 (twenty eight) individuals: semen pre-vasectomy and seminal fluid (post-vasectomy) stains, stored from 2004 to 2014 at room temperature were used. Three cutouts of 1.5 cm in diameter (punch) were taken from central region of each spot. It was used the QIAamp DNA Mini kit (Qiagen) to extract DNA with an adapted protocol followed by quantification by Nanodrop equipment. Genetic profiles were obtained using ESI17PowerPlex R (Promega). Capillary electrophoresis was performed on the ABI PRISM 3500XL DNA Analyzer. The DNA extraction was successful in all punch analyzed, and its concentration ranged from 1.1ng/uL to 23.3ng/uL in the pre-vasectomy and from 0.8ng/uL to 7 ng/uL in postvasectomy punch. The samples had suitable purity, reflecting the presence of few contaminants. Currently, the techniques of DNA amplification are extremely sensitive and capable of assessing human DNA in small quantities generating partial or full profiles, trespassing situations such as long storage periods in cotton fabric. These data can be used as a benchmark for forensic analysis in cases of semen analysis. IntroductionThe need to obtain genetic profiles to be added to DNA databank is a recent reality in Brazil, since only in 2012 the legislative started to regulate the creation and the use of the National Bank of Genetic Profiles (NBGP), which counts with CODIS technology [1]. It is well known that because of the nature of the crime, sexual assault tends to leave traces that allow the identification of the perpetrator in about 50% of cases [2], and due to the possibility of additional offenses by the criminal, it is recommended to insert the genetic profiles generated in DNA banks [3]. In parallel, there are situations where the only materials available for analysis are traces, such as semen stains on the victim's clothing. The absence of spermatozoa in the ejaculate of azoospermic individuals increases the difficulty of extracting DNA for profile analysis, especially if the biological samples are impregnated on fabric and stored for years. With the launch of NBGP, the analysis of cases without suspects lead to the necessity of generating autosomal genetic profiles for sex offenders. The aim of this study was to evaluate the possibility of obtaining autosomal and Y-STR profiles from ejaculate stains of 28 pre and post-vasectomy individuals stored for 10 years in cotton fabrics.

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Section: Discussionsupporting

confidence: 95%

Stains of ejaculated pre and post-vasectomy: Purity and sufficient quantity of recovered DNA after 10 years of storage

Mautoni

Astolphi

Mello

et al. 2015

Forensic Science International: Genetics Supplement Series

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“…The Erase Sperm Isolation Kit uses an entirely new approach to removing the unwanted residual DNA from the victim, namely by destroying the DNA with a nuclease [20]. The current study demonstrates that use of a nuclease, rather than physical separation methods to remove the residual DNA of the victim, results in the almost complete absence of female DNA as determined by the STR profiles of the male fractions of samples consisting of mock sexual assault cases (female buccal swab cuttings spiked with a known number of sperm), timed post-coital vaginal swabs, and evidence taken from rape victims.…”

Section: Discussionmentioning

confidence: 99%

“…In this study, the lysis buffer contained SDS detergent, which inhibits the nuclease (DNase I) and must be removed before adding the nuclease. Another approach to using a nuclease that does not require a buffer change involves using Triton X-100™ (Sigma Aldrich, Saint Louis, MO, USA), a non-ionic detergent that does not inhibit DNase I, in the lysis buffer instead of SDS [20]. A product using a nuclease to remove residual DNA from the sperm pellet without a buffer change has recently been commercialized by PTC Labs (Columbia, MO, USA) as the Erase Sperm Isolation Kit.…”

Section: Introductionmentioning

confidence: 99%

Isolating DNA from sexual assault cases: a comparison of standard methods with a nuclease-based approach

Garvin¹,

Fischer

Schnee-Griese

et al. 2012

Invest Genet

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BackgroundProfiling sperm DNA present on vaginal swabs taken from rape victims often contributes to identifying and incarcerating rapists. Large amounts of the victim’s epithelial cells contaminate the sperm present on swabs, however, and complicate this process. The standard method for obtaining relatively pure sperm DNA from a vaginal swab is to digest the epithelial cells with Proteinase K in order to solubilize the victim’s DNA, and to then physically separate the soluble DNA from the intact sperm by pelleting the sperm, removing the victim’s fraction, and repeatedly washing the sperm pellet. An alternative approach that does not require washing steps is to digest with Proteinase K, pellet the sperm, remove the victim’s fraction, and then digest the residual victim’s DNA with a nuclease.MethodsThe nuclease approach has been commercialized in a product, the Erase Sperm Isolation Kit (PTC Labs, Columbia, MO, USA), and five crime laboratories have tested it on semen-spiked female buccal swabs in a direct comparison with their standard methods. Comparisons have also been performed on timed post-coital vaginal swabs and evidence collected from sexual assault cases.ResultsFor the semen-spiked buccal swabs, Erase outperformed the standard methods in all five laboratories and in most cases was able to provide a clean male profile from buccal swabs spiked with only 1,500 sperm. The vaginal swabs taken after consensual sex and the evidence collected from rape victims showed a similar pattern of Erase providing superior profiles.ConclusionsIn all samples tested, STR profiles of the male DNA fractions obtained with Erase were as good as or better than those obtained using the standard methods.

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“…the question about the advantages of using both classical approaches for extracting DnA from post-coital samples, differential lysis (10,16,17,43) or direct organic extraction of DnA (30,41) from all the gathered biological material, is still under discussion. Various modified methods for DNA extraction (7,15,24,28) which aim to improve the quantity and quality of the extracted DnA and to minimize the loss of biological material during the separation of the male component from the female one in mixed samples (3,22), have been developed.…”

Section: Introductionmentioning

confidence: 99%

Modified Practical Approach in Repeated DNA Studies of Biological Evidence of Sexual Assault

Apostolov¹

2013

Biotechnology & Biotechnological Equipment

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DNA Preparation from Sexual Assault Cases by Selective Degradation of Contaminating DNA from the Victim

Cited by 42 publications

References 17 publications

Stains of ejaculated pre and post-vasectomy: Purity and sufficient quantity of recovered DNA after 10 years of storage

Stains of ejaculated pre and post-vasectomy: Purity and sufficient quantity of recovered DNA after 10 years of storage

Isolating DNA from sexual assault cases: a comparison of standard methods with a nuclease-based approach

Modified Practical Approach in Repeated DNA Studies of Biological Evidence of Sexual Assault

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