What are genomes made of?

Your genome is made of a chemical called DNA. The letters of DNA stand for deoxyribonucleic acid but that's not really important. What is important is the unique shape of DNA.

Why is DNA's shape important?

DNA is shaped like a twisted ladder. Imagine a ladder made of rubber. If you held the bottom of the ladder firmly and twisted the top, the shape you would create is the same shape that your DNA has. Researchers call this shape a 'double helix'.

The rungs on the DNA ladder are called base pairs: these do the important job of being the instructions. These base pairs can break, allowing the sides of the helix to unravel (roll your mouse pointer over the image). This special property is what allows DNA to copy itself, and to act as the instructions.