Click on the image or the + sign to view larger image		Crystals of DNA binding to one of its repair proteins These crystals have been photographed as they are growing from a solution of DNA with a pure protein binding onto it. Each cell in your body has 3 billion base pairs of DNA encoding all the genes it needs to make it work, but damage by chemicals and mistakes in copying can sometimes occur. This is one of a number of proteins that fixrs the damage after it has happened. If an area of damage is missed by the repair proteins it could lead to faulty gene functioning in the cell and in some cases to cancer. If the fault is in an egg or sperm cell it could lead to a birth defect in any child who inherits it. These very pure crystals are grown in order to analyze the structure of the protein and how it binds to the DNA using a technique called X-ray crystallography. Credit: Bernard O’Hara and Renos Savva