Anyone with an interest in Science or just anyone who checks the news regularly will have no doubt heard about the NASA discovery of a new bacterium in a Californian lake that thrives on the toxic chemical arsenic. This has massive implications for the possibility of extraterrestrial life as originally it was thought (based on life on Earth) that oxygen, hydrogen, carbon, nitrogen, sulphur and phosphorus were necessary for life. However, this new bacterium is able to use arsenic in it's molecular make up instead of phosphorus and even incorporate it into its DNA.
It is not yet known how arsenic gets incorporated into its molecules or how they operate but that will perhaps come in time. The ability of this bacterium to live not only with arsenic but also to incorporate it into its molecular make-up and DNA increases the possibility of life on planets that aren't Earth-like and contain all sorts of chemicals toxic to us.
However, the scientific community is split over these results, with many questioning their validity. Some of the doubt is coming from the fact that in order to measure the modified DNA it has to be put into a water-containing gel, which would rapidly dissolve any arsenate molecules and so any hypothesis that arsenate might replace phosphate in biomolecules must take this into account. Some are playing with the idea that perhaps arsenate was being stabilized by yet another molecule or being stuffed away in shielded bubbles in huge amounts.
Only the coming months will prove whether or not these finding are true. In the past there have been many other discoveries published but later proved wrong after further testing, but hopefully this will not be one of them as the possibilities it opens to extraterrestrial life are just too intriguing.