Video transcript: ‘X-shape’ not true picture of chromosome structure, new imaging technique reveals
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Video shows illustration of a single cell
Dr Peter Fraser, The Babraham Institute
What we're seeing here is an illustration of a single cell and we're slowing travelling toward its nucleus, the hub of genetic material. Inside you can see chromosomes, the familiar X-shape blob of DNA. But chromosomes don't really exist like this in most cells, in fact this is only a fleeting structure. Most of the time chromosomes look like this.
Video shows microsopic image of four cell nuclei with stained DNA
These are four typical cell nuclei in which we've stained all of the DNA with a blue dye and one of the chromosomes in green. You can see it looks nothing like the familiar X-shape cartoon structure of chromosomes.
Video shows 3D model of chromosomes
Using a new technique that we've developed, we've created a much more accurate picture of how the DNA folds within a chromosome. The DNA is represented here by the single strand that weaves through the 3D structure. This is how DNA exists within a chromosome in its usual state, a state in which all the important functions of the genome are operating and controlled.
Video shows a comparison of the microscopic image and 3D model of chromosomes
3D models of chromosomes allow us to map specific genes and other important genomic features onto the structures. Putting DNA into its proper context like this is important because the folding of DNA and the position of genes on a chromosome contribute to genome control.
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- Cell animation www.sciencephoto.com