It has come to light recently that DNA makes up only half of the material inside chromosomes. This is less than what was thought prior to this study. Almost half of the structure is a sheath which surrounds the genetic material in the chromosome. During this study, at the University of Edinburgh, 3D models were produced for the first time ever, of each of the 46 human chromosomes. A microscopy technique was developed in order to study the structure called 3D-CLEM. This method uses a combination of electron microscopy and light along with computational modeling software which gives high-resolution 3D images of chromosomes.
When looking at these images, there is material containing DNA and supporting proteins which is said to account for 53 and 70 percent of the total content of the chromosome where as the remaining percentage is composed of chromosome periphery. Prior to this study, it was assumed that chromosomes were composed primarily of chromatin.This new research brings questions into how chromosomes are built and segregation during cell division since there is thick layer of this material covering the genetic material. This groundbreaking study into the models of chromosomes is amazing and can lead way to so much more information regarding the human chromosomes.