DNA: the 'smartest' molecule in existence?

24 April 2013 Last updated at 17:55 By Jennifer Green and Dhruti Shah BBC Science

DNA is the molecule that contains and passes on our genetic information. The publication of its structure on the 25th of April 1953 was vital to understanding how it achieves this task with such startling efficiency.

In fact, it's hard to think of another molecule that performs so many intelligent functions so effortlessly. So what is it that makes DNA so smart?

For such a huge molecule, DNA is very stable so if it's kept in cold, dry and dark conditions, it can last for a very, very long time. This is why we have been able to extract and analyse DNA taken from species that have been extinct for thousands of years.

It's the double-stranded, double-helix structure of DNA that stops it falling apart.

DNA's structure is a bit like a twisted ladder. The twisted 'rails' are made of sugar-phosphate, which give DNA its shape and protect the information carrying 'rungs' inside. Each sugar-phosphate unit is joined to the next by a tough covalent bond, which needs a lot of energy to break.

In between the 'rails', weaker hydrogen bonds link the two halves of the rungs together. Individually each hydrogen bond is weak - but there are thousands of hydrogen bonds within a single DNA molecule, so the combined effect is an extremely powerful stabilising force.

It's this collective strength of DNA that has allowed biologists to study genes of ancient species like the woolly mammoth - extinct but preserved in the permafrost.

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This short animation explains everything else you need to know about DNA.

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DNA: the 'smartest' molecule in existence?