Arrangement and characterization of repetitive sequence elements in animal DNAs.

Abstract

Recent investigations carried out in our laboratory have shown for several animal DNAs that repetitive and nonrepetitive sequences are interspersed in a generally ordered manner. The basic type of experiment on which this conclusion rests begins with the reassociation of trace quantities of long, labeled DNA fragments with short, unlabeled fragments present in excess. The mixture is incubated to low C0t, so that only repetitive sequences are reassociated, and is then passed over hydroxyapatite. Long, radioactive fragments which bind to the hydroxyapatite contain repetitive sequence elements paired with short, unlabeled DNA fragments. In the DNAs which have been studied in this manner, most of the bound labeled DNA strands include nonrepetitive sequences as well as the repetitive sequence elements causing the binding. Therefore, it is evident that the repetitive and nonrepetitive sequence elements must be closely interspersed in the genome. We...