Is there anybody out there?

The film: 'Contact' (1997) is based on the book by Carl Sagan, an atheist, who believes in life on other planets. During the film a signal is received from space, consisting of Prime Numbers. This indicates that there is intelligence out there. SETI (The Search for Extra-Terrestrial Intelligence) are always looking for signs of life out there. All that would be needed to move from science fiction to science fact is a code (as in the film).

DNA: Deoxyribonucleic acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses.

Instructions are found in DNA; DNA is found in every cell in our bodies. Why has nobody realised...?