A rapid method for purification of organelles for DNA isolation: self-generated percoll gradients.

Self-generated Percoll gradients have been used for rapid purification of crude chloroplasts and mitochondria, obtained by common differential centrifugation techniques. Such purified organelles were used for isolating DNA from safflower (Carthamus tinctorius L.), carrot (Daucus carota L.), various Solanaceae, and numerous somatic hybrids. The method is simple, has the advantage of not requiring DNase, and is particularly well suited when only limited amounts of aseptically grown shoots are available. As judged by restriction enzyme analyses and chloroplast DNA cloning experiments, the DNAs are of sufficient purity for many molecular biological applications without CsCl gradient purification.