Protein machines inside our cells that read the DNA read 3 base codes at a time. Each base code has 4 possible values, 4³ (cubed) is 64. This means each coden has 64 possible values. Just enough to represent every type of amino acid and have some characters left over for starting and stopping a gene sequence.
DNA amazes me because it is so clever. It is pulled in half down the middle without breaking the long chains. Then the DNA is read only on one side, the other side is a copy in reverse and is used to duplicate the DNA molecule. Then the two half DNA strands are zipped back together again.
DNA and the proteins that manipulate it are machines. Every cell on Earth interacts with DNA the same way and follows the same rules. They read the same side of the DNA molecule and in the same direction and the codes to start and end a gene sequence are the same for all cells as far as I know.
