An Application of Salivary DNA in Twin Research of Chinese Children

Abstract

S ince saliva collection is noninvasive, painless and inexpensive, it may become an alternative to obtain genomic DNA, which is critical to evaluate zygosity and the role of genetic factors in twin research. This study provided a rough description of salivary DNA in Chinese twin children, and presented the DNA yield and quality extracted from saliva in a large-scale children sample, which supplied an example for saliva sample using in genetic epidemiology. Three milliliters of saliva was collected from 356 twin children aged 6 to 15, and DNA was extracted by a com mercial DNA isolation kit. The DNA yield and purity was determined by spectrophotometry at 260nm and 280nm. The zygosity determination of the same-sex twins and the assay of Polymerase Chain Reaction-Restriction Fragment Length Polymorphism indicated the quality of salivary DNA. The amount of extracted DNA from three milliliters of saliva was about 34.91µg (2.20 ~ 122.04µg), average OD 260/280 values was 1.84. Saliva DNA is a reliable sample for the determination of twins' zygosity. We conclude that saliva may be a feasible and reliable source of DNA for genetic epidemiology studies, especially for twin research.

Nonshared Environment and Monozygotic Adolescent Twin Differences in Effortful Control

“…This method of determination has an accuracy rate of 99.0% (Rogers, Cole, Lan, Crossa, & Demerath, 2007). Reliability and validity have been supported in a Chinese sample (Chen et al, 2010;Zhang & Ji, 2008).…”

Quality of DNA extracted from saliva samples collected with the Oragene™ DNA self-collection kit

“…Koni et al [1] recently made clear the limitations of low-quality DNA in biobanks, in addition to summarizing previous studies that used saliva collection to obtain DNA. The concentration of DNA extracted from blood leukocytes processed by saline extraction is 28.4 μg (11.3-59.5 μg) from 2 mL of blood [5], whereas the quantity of DNA obtained by saliva collection is 34.91 μg (2.20 – 122.04 μg) from 3 mL of saliva [6]. Although saliva collection provides smaller amounts of DNA than blood, this biological sampling method has been widely used, especially because it requires more simple logistics, including self-collection by study subjects and sample mailing [7-11].…”