DNA usually comes in the famed double helix shape. However, scientists have discovered DNA in other forms as well such as the G-quadruplex and i-motif.
DNA was discovered by the Swiss chemist Friedrich Miescher in 1869. Miescher extracted the molecule from the white blood cells collected at a local hospital and called it nuclein. The chemical composition of this new molecule was so shocking that Miescher delayed publishing his results until 1871.
The smallest documented genome belongs to the bacteriaNasuia deltocephalinicolawith 112,091 nucleotides and 137 protein-coding genes.
The largest documented genome belongs to the plant Paris japonica with ~150,000,000,000 nucleotides. (This is 20 billion more than the runner up – the marbled lungfish Protopterus aethiopicus – that has 130 billion nucleotides.)
The human genome is just over 3 billion nucleotides. Scientists are still trying to sequence all of them! The latest step forward was by researchers in the Telomere-to-Telomere consortium who added 200 million base pairs. Their results can be found in the pre-published paper.
If you uncoiled all the DNA in a person’s cells and put them end to end the DNA would reach far into outer space. How far? The equivalent of traveling round trip between Pluto and the sun seventeen times. (Napkin calculation: Each cell has ~6-cm long strand of DNA coiled tightly within it and there are thirty-seven trillion cells in the body. Pluto’s average distance from the sun is 5,906,380,000 kilometers.)
You share 99.9% of your DNA with every other human. You also share 85% of your coding DNA with a mouse, 60% with a fruit fly, and 41% with a banana.
DNA ‘fingerprints’ can be used to place a suspect at the scene of the crime, solve cold cases, and exonerate innocent people. In the US there are 375 DNA exonerees to date.
In case the world ends, the International Space Station has an Immortality Drive with the digitalized human DNA sequences on it. Some noticeable genomes include that of the physicist Stephen Hawking, comedian Stephen Colbert, Playboy Playmate Jo Garcia, game designer Richard Garriot, Pro Wrestler Matt Morgan, and athlete Lance Armstrong.