It is always a surprise when a new invention or discovery turns out to have been anticipated by nature, as with the 2 billion year old natural reactor at Oklo in Gabon, Africa.
Dieter Braun of Rockefeller University, New York, USA, and colleagues have shown that the polymerase chain reaction (PCR), which is nowadays used to copy DNA in huge quantities in laboratories around the world, may occur naturally, driven by the simple process of convection.
In the laboratory, DNA is mixed with an enzyme and cycled through temperatures between 60 and 90 °C. The new idea here is that volcanic vents in the ocean might push chemical mixtures from a hot region near the vent to cooler regions. There, the mixtures' temperature would drop, allowing them to fall back towards the vent, to repeat this motion and form a convection cell where PCR or similar reactions could occur automatically.
The same process could also take place on a smaller scale anywhere that such convection cells form, and could offer an important hint as to how life began.
Further reading
Dieter Braun et al. 2003 Phys. Rev. Lett. 91 158103.