DNA of ciliated protozoa

DNA was isolated from macronuclei and micronuclei of the ciliated protozoan, Stylonychia mytilus under conditions that minimize the possibility of DNA degradation. Macronuclear DNA has an S value of 10 to 11 in sucrose gradients. Macronuclear DNA has an average molecular weight of 1.15×10⁶ daltons and a range of molecular weights of 1.0×10⁶ to 1.95×10⁶ daltons. The average length of macronuclear DNA, measured by electron microscopy, is 0.80 microns and the range is 0.2 to 2.2 microns. Almost all micronuclear DNA pieces are too long to be measured by electron microscopy. The shortest piece of micronuclear DNA found was 15.0 microns in length.