Denatured, single-stranded DNA fragments can reassociate into complementary double strands. The single-stranded DNA concentration (C) can be plotted against a logarithmic scale of the product of C0t (initial concentration of DNA single strands), and t (time).

The half-reaction time C0t1/2 increases as the fragment size increases, so this can be used to estimate genome sizes. Repetitive DNA sequences in some eukaryotic DNA allow them to have much shorter C0t1/2.