You've got to hand it to the chemists

The origin of chiral asymmetry, or homochirality, in nature has been a long-standing puzzle in science. Why are almost all amino acids in nature left handed and almost all sugars right handed, for instance? Now, a team at Imperial College London have discovered that amino acids themselves may have been the amplifying molecules that tipped the balance in the early stages of life. Donna Blackmond and her colleagues measured the rates of reactions catalysed by the amino acid proline. Using sensitive calorimetry techniques they observed an enantiomeric excess even without any chiral bias in the reaction. The excess was only small but might have been enough in pre-biotic conditions to push nature one way and not the other.