Assay for the quantification of small-sized fragmented genomic DNA

This paper presents a simple assay for the direct quantification of small-sized (up to 1000 bp) fragmented DNA based on the differential separation between large- and small-sized DNA by polyethylene glycol precipitation. The assay can be applied to as low as 1 μg ml−1 DNA and has a very low DNA detection limit (0.01 μg ml−1 fragmented DNA), which can be further lowered at least 10-fold with anion exchange chromatography. The assay quantifies for the first time a more direct indicator of the extent of DNA damage than the usually assessed DNA nicks and base modifications, since small-sized fragmented DNA represents an unrepairable DNA damage of necrotic and apoptotic events that are related to normal and abnormal biological conditions.