Researchers have painted a picture of the real shape of chromosomes commonly believed to be "X-shaped."

The team produced 3D models that give a more accurate visualization of the misunderstood chromosomes, a BBSRC press release reported.

"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," Doctor Peter Fraser of The Babraham Institute, said.
"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," he said.

In order to determine the chromosomes' shape when in between division phases, the researchers made "thousands of molecular measurements" within a single cell. Using advanced computer systems, the team was able to turn these measurements into a stunningly specific 3D portrait of the microscopic entities.

"These 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 these 3D models, we have begun to unravel the basic principles of chromosome structure and its role in how our genome functions," Fraser said.

The simulation can help people look at chromosomes like never before.

"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. These truer pictures help us to understand more about what chromosomes look like in the majority of cells in our bodies. The intricate folds help to unravel how chromosomes interact and how genome functions are controlled," Douglas Kell, BBSRC Chief Executive, said.

See Fraser's blog post on the subject.

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