The organization and repair of DNA in the mammalian chromosome. II. A gradient‐shape‐induced speed dependence affecting DNAs larger than T₄ DNA

Abstract

SynopsisThe addition of a lytic layer to a preformed linear sucrose gradient induces a temporary (up to half a day) initial gradient of considerable steepness which retards the sedimentation of large (>T,) DNAs. Centrifugation a t sufficiently slow angular velocities permits the temporary initial gradient to disappear and therefore the sedimentation distance increases, yielding a rotor speed dependent effect on sedimentation distance. Gradients which are free of this effect are described and shown to permit mouse leukemia cell DNA to sediment independently of rotor speed (5-30 krpm).