While many high school biology classes continue to teach the chromosome as an X-shaped bundle of DNA, scientists have used new imaging techniques to reveal the structure’s true shape.
As it turns out, chromosomes form less of an X and more of an amorphous blob-like shape. Funded by the Biotechnology and Biological Sciences Research Council (BBSRC), scientists at the Babraham Institute, University of Cambridge, and the Weizmann Institute used 3-D modeling techniques to represent the cell structure in its most natural state. The characteristic X, the researchers concluded, occurs only when the cell is on the brink of division.
"The vast majority of cells in an organism have finished dividing and their chromosomes don't look anything like the X-shape,” explained Dr. Peter Fraser, of The Babraham Institute, in a BBSRC news release. “Chromosomes in these cells exist in a very different form and so far it has been impossible to create accurate pictures of their structure."
The new technique involves creating thousands of molecular measurements of chromosomes inside single cells, then extrapolating each measurement into a three-dimensional visual portrait that, for the first time, allows scientists to understand DNA’s true form so intricately.
"These unique images not only show us the structure of the chromosome, but also the path of the DNA in it,” Fraser added, “allowing us to map specific genes and other important features. Using these 3D models, we have begun to unravel the basic principles of chromosome structure and its role in how our genome functions."
Chromosomes are important to the human body because they contain essential DNA makeup, along with many genes and regulatory elements. Being able to more accurately visualize the chromosome allows scientists to observe a range of potential risk factors regarding human health. One such threat is chromosomal instability, which takes place when a cell’s chromosomes cannot split properly and results in mitotic catastrophe or the progression of cancer.