Renaturation of DNA from ultrasonically fragmented chromatin

The rates of renaturation of ultrasonically treated DNA, isolated from fragments of rat liver chromatin, were compared. Chromatographic fractionation on hydroxylapatite was used to fractionate the denatured and renatured DNAs. It was shown that DNA fraction 1 renatures considerably faster than fraction 2. The results are compared with previously published data on the specificity coefficient of DNA, the content of basic amino acids and alkali-labile phosphorus of the protein in the corresponding fragments of the chromatin. The possible functional role of these fragments in the genome is discussed.