Tool quantifies differences in DNA repair among individuals

CometChip — a high-throughput tool developed with NIEHS funds to quantify DNA damage — can be used to measure differences among individuals in terms of their bodies’ capacity to repair such damage, according to a recent institute-supported study. That information may help to shed light on how much of a person’s disease risk is due to genetic versus environmental factors.

DNA damage can lead to mutations that drive diseases such as cancer, but damage levels and resulting genetic mutations can vary greatly among individuals due to differences in their genetics. Relatively few studies have evaluated variation in DNA repair capacity between individuals, and most of those involved small sample sizes.

Using CometChip, researchers explored DNA repair within individuals over time. They measured levels of DNA damage in cells collected from more than 50 people at multiple timepoints following oxidative damage and used Comet measurements in cultured cells as a control. Their analysis included more than 1,500 samples and more than 150,000 data points.

The team reported significant variability in DNA repair efficiency among individuals, with a 9.5-fold difference between the fastest and slowest repair rates. The researchers also observed differences in repair rates between visits for the same individual, indicating that DNA damage levels vary over time and may be affected by environmental factors.

According to the authors, CometChip may be useful for detecting differences in DNA repair capacity in large-scale clinical studies. They note that identifying people with reduced DNA repair capacity could inform personalized medical treatments.

Citation: Ngo LP, Kaushal S, Chaim IA, Mazzucato P, Ricciardi C, Samson LD, Nagel ZD, Engelward BP. 2021. CometChip analysis of human primary lymphocytes enables quantification of inter-individual differences in the kinetics of repair of oxidative DNA damage. Free Radic Biol Med 174:89–99.

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