The Physics of DNA and Chromosomes

Each of the tens of trillions of cells making up your body contains about two metres of DNA, which need to fit within the 10 microns container that is its nucleus—roughly a tenth of the diameter of a human hair. How is the DNA arranged in such a tight spot? A liver and a brain cell contain exactly the same genetic material, as they come from the same egg cell, yet they work very differently, because the patterns of genes that are on and off in the two is completely distinct. How is this at all possible? Biophysicists have found general principles that are beginning to answer these and similar questions. In this ebook we explore some of these principles, and describe a selection of topics where physicists have contributed to our current understanding of DNA and chromosomes.