The effect of age on DNA concentration from whole saliva: Implications for the standard isolation method
Bibliographic record
Abstract
OBJECTIVES: Adequate quantity and quality of the DNA isolated from saliva samples are crucial for ensuring successful genotyping rates in genetic studies. However, there is little information about these issues when saliva samples are collected from children. The objectives of this study were to assess whether there are differences in DNA quality or quantity isolated from saliva samples of children at different ages and adolescents compared to adults and, if so, to establish a modified protocol to improve and standardize DNA isolation from saliva samples of children. METHODS: Saliva samples were collected with Oragene DNA Sample Collection Kit from 41 healthy subjects including children of different ages, adolescents, and adults. Quantity and quality of isolated DNA were determined spectrophotometrically. RESULTS: DNA concentration and age were positively correlated (r = 0.676, P < 0.001). A high percentage of samples from children below 12 years yielded DNA concentrations <100 ng/µL and DNA quality a260/a280 ratios of <1.8. Modifying the standard DNA isolation method raised DNA quantity and quality in these critical samples. CONCLUSIONS: Age determines, at least in part, the high variability observed in the concentration of DNA isolated from saliva samples. This fact should be taken into account for a better standardization of the DNA isolation to ensure DNA banking in large-scale genetic studies involving children.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.056 | 0.136 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".