Coils and corkscrews

Two scientists, Francis Crick and James Watson, finally began to find out the basics of how genes worked and how they copied themselves. This was back in 1953 when they discovered what the stuff that makes all genes everywhere really looked like. This stuff is called DNA (for you clever kids, that stands for deoxyribonucleic acid - got that?) and it looks like a double corkscrew. It seems that DNA is the cassette tape which stores all the information about how to make a new cell - or person or penguin. It all coils up very small to pack away into the tiny space in the centre of cells.

Copycat
How does the DNA copy itself? Because it's made of two corkscrews - called a double helix - hooked together, it can unwind. As it does this, it attracts the right new bits to join the hooks which run down its middle - a bit like the legs on a millipede.

And so one strand rebuilds a new mirror-image of itself, just as its mirror-image partner is doing nearby. So one DNA molecule becomes two perfect copies. Clever stuff, eh?

How the DNA itself then organises all the stuff inside a cell to make whatever it needs - like proteins - is complicated. Scientists still don't understand all the things that have to happen to make what starts as just one cell into a human being or a whale. It's taken 3,500 million years for nature to develop all this wonderfully clever yet tiny machinery to build bodies. So it's not surprising that scientists don't understand all that much yet. This makes the next bit rather worrying.

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