Chloroplast deoxyribonucleic acid Isolation: purity achieved without nuclease digestion

Abstract

Chloroplasts, obtained from plant tissues homogenized in liquid nitrogen, were freed of nuclei on silica sol gradients. Buoyant density analysis of denatured–renatured DNA and the clarity of restriction fragment patterns demonstrate the purity of these preparations. In this manner, chloroplast DNA free of substantial nuclear DNA contamination was obtained from several plant species without the use of a deoxyribonuclease digestion step.