Elsevier

Analytical Biochemistry

Volume 353, Issue 2, 15 June 2006, Pages 272-277
Analytical Biochemistry

Evaluation of saliva as a source of human DNA for population and association studies

https://doi.org/10.1016/j.ab.2006.03.021Get rights and content

Abstract

A simple noninvasive procedure for saliva sample collection and DNA extraction was developed. On average, the amount of human DNA (as measured by a TaqMan-based assay) was about 11.4 μg/mL saliva, which is more than can be obtained from other noninvasive samples such as cheek swabs. However, the presence of large amounts of nonhuman DNA (up to 90% of the total extracted DNA) in saliva samples does necessitate DNA quantitation methods that are specific for human DNA. We were able to reliably and accurately type different genetic markers (mDNA sequences, Y-chromosomal single-nucleotide polymorphisms, and autosomal microsatellite loci) from saliva samples stored for up to 30 days at 37 °C, making this method well-suited for field conditions and convenient transportation of samples back to the laboratory. Thus, saliva can be considered a reliable source of DNA for a wide variety of genetic studies.

Section snippets

Samples

Five milliliters of saliva was collected from each of five females and five males. Samples were divided into one 2-mL and three 1-mL aliquots; each aliquot was mixed with an equal volume of lysis buffer (50 mM Tris, pH 8.0, 50 mM EDTA, 50 mM sucrose, 100 mM NaCl, 1% SDS). Additionally, cheek cell samples were collected from the same individuals using two sterile swabs per individual (Whatman sterile Omniswab, Fisher Scientific). Each donor brushed the inside of each cheek 30 times with each sterile

Results and discussion

Amounts of human DNA in extracts from saliva and cheek cell samples collected from 10 individuals and percentages of human DNA are listed in Table 1. The amount of DNA was generally consistent across different storage times, except that there was less DNA in the fresh sample than in the stored samples for individuals 3, 6, and 10; the reason for the decrease in the amount of DNA in these fresh samples is unknown, but may reflect technical problems with these extractions. Overall, there was no

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Cited by (0)

1

Present address: Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauer Strasse 108, D-01307 Dresden, Germany.

2

Present address: Department of Forensic Molecular Biology, Erasmus University Medical Center Rotterdam, NL-3000 DR Rotterdam, The Netherlands.

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