Increasing DNA extraction yield from saliva stains with a modified Chelex method

Sweet, David; Lorente, Miguel; Valenzuela, Abel; Lorente, JoséA.; Álvarez, Juan Carlos

doi:10.1016/s0379-0738(96)02034-8

Cited by 96 publications

(52 citation statements)

References 16 publications

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“…Amplification results demonstrate the absence of contamination by DNA from the subject's skin (16). Positive amplification results where obtained from HUMTH01, HUMVWA, and HLA-DQA1 which indicate that salivary DNA of sufficient quality and quantity was recovered (results not shown).…”

Section: Resultsmentioning

confidence: 95%

An Improved Method to Recover Saliva from Human Skin: The Double Swab Technique

Sweet¹,

Lorente

et al. 1997

Journal of Forensic Sciences

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REFERENCE:Sweet D, Lorente M, Lorente JA, Valenzuela A, Villanueva E. An improved method to recover saliva from human skin: The double swab technique. J Forensic Sci 1997;42(2): 320-322. ABSTRACT:Human bite mark evidence is often found in violent crimes. Due to the difficulties of physically comparing an injury site on elastic and curved skin surfaces to the teeth of a suspect, the authors have considered using salivary DNA evidence to identify the bite perpetrator. Several techniques were evaluated to determine the best method of recovering saliva from human skin before extracting genomic DNA from the collection substrate. A classical stain recovery technique using a wet cotton swab was tested against one utilizing a wet filter paper. Additionally, a new method, referred to as the double swab technique, using a wet cotton swab followed by a dry cotton swab was also evaluated. After recovering a dlied saliva stain, DNA was extracted using the modified Chelex method, quantified using the slot-blot procedure, and amplified at three polymorphic loci. The double swab technique showed the highest percentage recovery of saliva from human skin among the three methods studied. This technique is suggested as an improvement over the classical single wet cotton swab technique.KEYWORDS: forensic science, saliva, bite marks, odontology, serology, forensic evidence Teeth are often used as a weapon in violent crimes when one person attacks another, or in self-defense against an attacker (1). Human bite marks are found in cases of homicide, sexual assault, and crimes of family violence including child and spousal abuse (2). Conventional analysis strategies attempt to physically compare the injury pattern found on the victim's skin to the teeth of the suspected biter to reach conclusions regarding relative concordance (3).In addition to considering bite marks as examples of physical evidence, the authors have also focused their attention on bite ~Forensic odontologist, UBC Faculty of Dentistry, Vancouver, BC Canada.2Assistant professor, associate professors, and professor, respectively, Faculty of Medicine, University of Granada, Spain.This project was supported by grants from the Ministry of Education and Science of the Government of Spain (PB93-1155), the Plan Propio de Investigaci6n of the University of Granada, Spain, and by the Dentistry Canada Fund/Warner Lambert Foundation, Ottawa, Canada.Received 3 June 1996; and in revised form 31 July 1996; accepted on 2 Aug. 1996. marks as biological evidence. It is assumed that forensically significant amounts of saliva are deposited during biting, sucking, or licking and that traces of salivary evidence can be recovered for identity testing.Determination of the origin of a saliva stain using conventional markers is not highly sensitive nor discriminatory. The limited detectability of blood group antigens and polymorphic proteins due to their low concentrations is an inherent problem (4). Genomic DNA testing has increased sensitivity compared with conventional saliva testing methods ...

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Section: Resultsmentioning

confidence: 95%

An Improved Method to Recover Saliva from Human Skin: The Double Swab Technique

Sweet¹,

Lorente

et al. 1997

Journal of Forensic Sciences

Self Cite

236

141

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“…Mating between flies of this last genotype gave the results of Table 3. To investigate the presence of a P-element insertion in the offspring of Table 3, DNA was extracted from single animals by grinding the animal in 100µl 5% chelex-100 (Bio-Rad Laboratories) in an Eppendorf tube (Sweet et al 1996). The tube was then incubated for 30 min at 56°C and 8 min at 100°C.…”

Section: Isolation Of a Knock-out Mutantmentioning

confidence: 99%

Molecular Cloning, Genomic Organization, Developmental Regulation, and a Knock-out Mutant of a Novel Leu-rich Repeats-containing G Protein-coupled Receptor (DLGR-2) from Drosophila melanogaster

Eriksen

Hauser²,

Schiøtt³

et al. 2000

Genome Res.

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After screening the Berkeley Drosophila Genome Project database with sequences from a recently characterized Leu-rich repeats-containing G protein-coupled receptor (LGR) fromDrosophila (DLGR-1), we identified a second gene for a different LGR (DLGR-2) and cloned its cDNA. DLGR-2 is 1360 amino acid residues long and shows a striking structural homology with members of the glycoprotein hormone [thyroid-stimulating hormone (TSH); follicle-stimulating hormone (FSH); luteinizing hormone/choriogonadotropin (LH/CG)] receptor family from mammals and with two additional, recently identified mammalian orphan LGRs (LGR-4 and LGR-5). This homology includes the seven transmembrane region (e.g., 49% amino acid identity with the human TSH receptor) and the very large extracellular amino terminus. This amino terminus contains 18 Leu-rich repeats—in contrast with the 3 mammalian glycoprotein hormone receptors and DLGR-1 that contain 9 Leu-rich repeats, but resembling the mammalian LGR-4 and LGR-5 that each have 17 Leu-rich repeats in their amino termini. The DLGR-2 gene is >18.6 kb pairs long and contains 15 exons and 14 introns. Four intron positions coincide with the intron positions of the three mammalian glycoprotein hormone receptors and have the same intron phasing, showing that DLGR-2 is evolutionarily related to these mammalian receptors. The DLGR-2 gene is located at position 34E-F on the left arm of the second chromosome and is expressed in embryos and pupae but not in larvae and adult flies. Homozygous knock-out mutants, where the DLGR-2 gene is interrupted by a P element insertion, die around the time of hatching. This finding, together with the expression data, strongly suggests that DLGR-2 is exclusively involved in development.[The nucleotide sequence(s) reported in this paper has been submitted to the GenBank/EMBL database with accession no. AF142343.]

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“…It has been shown that saliva can potentially be recovered and typed from bite marks [3][4][5]25 , cigarette butts, postage stamps, envelopes and other objects 9,22,24 . Stains of dried saliva are invisible, making its recognition and collection difficult 24 . However, the presence of saliva can be confirmed by an amylase assay 9 .…”

Section: Introductionmentioning

confidence: 99%

DNA extraction from human saliva deposited on skin and its use in forensic identification procedures

Anzai-Kanto¹,

Hirata²,

Hirata³

et al. 2005

Braz. oral res.

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Saliva is usually deposited in bite marks found in many homicides, assault and other criminal cases. In the present study, saliva obtained from volunteers was deposited on skin and recovered for DNA extraction and typing in order to evaluate its usefulness for practical case investigation and discuss the contribution of forensic dentistry to saliva DNA typing. Twenty saliva samples were colleted from different donors and used as suspects' samples. Five of these samples were randomly selected and deposited (250 µl) on arm skin. Saliva was collected from skin using the double swab technique. DNA from saliva and skin-deposited saliva samples was extracted by the phenol-chloroform method. DNA samples were amplified by PCR for DNA typing using a set of 15 STRs. The recovery of DNA from saliva deposited in the skin was 14 to 10 times lower than DNA quantity from saliva samples. DNA typing was demonstrated in 4 of 5 deposited saliva samples, the likelihood ratios estimated for these samples based on data of the Brazilian population were 1:11, 1:500, 1:159.140 and 1:153.700.123. Our results indicate that standardized procedures used for DNA collection and extraction from skin-deposited saliva can be used as a method to recover salivary DNA in criminal cases. However, it is important to observe that DNA recovery in forensic samples can be difficult. This study suggests that the analysis of saliva deposited on skin be incorporated into a criminal investigation since it may have great discriminatory power. DESCRIPTORS: DNA; Forensic dentistry; Saliva. RESUMO:A saliva é usualmente depositada em marcas de mordida encontradas em homicídios, agressões e outros crimes. Neste estudo, a saliva obtida de voluntários foi depositada na pele, recuperada para extração e tipagem do DNA, para avaliação de sua utilização e sua contribuição na odontologia legal. Vinte amostras de saliva foram coletadas de diferentes doadores e utilizadas como amostras de suspeitos. Cinco dessas amostras foram sorteadas e depositadas (250 µl) na pele. A saliva foi coletada da pele usando-se a técnica do duplo esfregaço. O DNA da saliva e das amostras de saliva depositadas sobre a pele foi extraído pelo método fenol-clorofórmio. As amostras de DNA foram amplificadas por PCR para a tipagem do DNA usando-se um grupo de 15 STRs. O DNA recuperado da saliva depositada na pele foi de 14 a 10 vezes menor que o DNA das 20 amostras de saliva. O perfil do DNA foi demonstrado em 4 de 5 amostras de saliva depositadas, e a razão de verossimilhança das amostras baseada em dados da população brasileira foi 1:11, 1:500, 1:159,140 e 1:153,700,123. Nossos resultados indicam que procedimentos padronizados utilizados para coleta e extração de DNA de saliva depositada podem ser utilizados como um método para recuperar DNA de saliva em casos forenses; entretanto, é importante observar que amostras forenses podem apresentar problemas na recuperação do DNA em quantidades adequadas. Este estudo sugere que a análise de saliva depositada sobre a pele pode ser incorporada ao...

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Increasing DNA extraction yield from saliva stains with a modified Chelex method

Cited by 96 publications

References 16 publications

An Improved Method to Recover Saliva from Human Skin: The Double Swab Technique

An Improved Method to Recover Saliva from Human Skin: The Double Swab Technique

Molecular Cloning, Genomic Organization, Developmental Regulation, and a Knock-out Mutant of a Novel Leu-rich Repeats-containing G Protein-coupled Receptor (DLGR-2) from Drosophila melanogaster

DNA extraction from human saliva deposited on skin and its use in forensic identification procedures

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