Chromosomes Not Shaped Anything Like an 'X' [VIDEO]

The picture of a chromosome neatly arranged into an "X" shape is oversimplified, to say the least, according to images taken by a new visualization method.

By creating thousands of molecular measurements of chromosomes in single cells, a team of researchers have developed three-dimensional models that more accurately portray their complex shape and the way in which the DNA within them folds.

"The image of a chromosome, an X-shaped blob of DNA, is familiar to many but this microscopic portrait of a chromosome actually shows a structure that occurs only transiently in cells -- at a point when they are just about to divide," Peter Fraser of the Brabraham Institute said in a statement.

"The vast majority of cells in an organism have finished dividing and their chromosomes don't look anything like the X-shape. Chromosomes in these cells exist in a very different form and so far it has been impossible to create accurate pictures of their structure."

Such complexity offers new insight into the intimate connection between a chromosome's structure -- and the way the DNA within it folds up -- and both when and how genes are expressed.

"Until now, our understanding of chromosome structure has been limited to rather fuzzy pictures, alongside diagrams of the all too familiar X-shape seen before cell division," said Douglas Kell, the chief executive of Biotechnology and Biological Sciences Research Council. "These truer pictures help us to understand more about what chromosomes look like in the majority of cells in our bodies."

According to Fraser, the "unique images not only show us the structure of the chromosome, but also the path of the DNA in it, allowing us to map specific genes and other important features." Using them, he explained, the researchers have already "begun to unravel the basic principles of chromosome structure and its role in how our genome functions."