A Swiss scientist named Friedrich Miescher found DNA back in 1869, hidden inside the nucleus of cells. He had no idea what it did. For almost a century, nobody else really did either. People thought it was probably just structural goo. The instructions for life, surely, had to be something more interesting.
It took until 1953 to figure out that DNA was the instructions for life - and that the shape mattered. James Watson and Francis Crick in Cambridge, England, published a paper showing DNA looked like a twisted ladder, called a double helix. The crucial clue was an X-ray photograph called “Photo 51,” taken by a brilliant chemist named Rosalind Franklin.
The shape was the answer. The two strands could be split apart and copied perfectly. That’s how cells pass on instructions when they divide, and how parents pass on traits to their kids. If you uncoiled all the DNA in your body and laid it end to end, it would stretch to the Sun and back about 70 times.
