A DNA Double Helix
Life on earth is based on right-handed DNA molecules and left-handed amino acids. Why life prefers certain handedness is not yet wholly understood. National Human Genome Research Institute

In what is claimed as a first, a Radboud University researcher has produced single-handed amino acid-like molecules in a simple reaction in a beaker in the lab.

The method is being likened to the processes that most probably took place in the primordial soup.

Most attempts to make the molecules in the lab end up with two versions. Life on earth is based solely on the left-handed variety of amino acids.

Many molecules invariably come in two variants (called stereoisomers) that are mirror images of each other. Chemically equivalent, the two variants differ vastly in biological terms. If one forms a medicine, the mirror image can be a toxin.

For some reason, organic life on earth makes use of one variant alone. The DNA is a right-handed helix as also glucose which is a right-handed molecule.

But it is different with amino acids. These raw materials of proteins are made in our bodies using only the left-handed variant.

Living organisms use only left-handed amino acids and right-handed sugars.

If provided with the right-handed versions of amino acids, cells ignore them, just as they ignore left-handed sugars. If forced under conditions, probably one could end up with equivalents of scrambled eggs.

Using simple building blocks, the Radboud chemists produced the single-handed molecule from a solution of a ketone and an amine.

For some reason, life on earth uses only right-handed DNA and left-handed amino acids.

Unlike earlier attempts at single handedness, they did not use any left or right-handed product to influence the formation.

René Steendam, the researcher in Astrochemistry at Radboud University, the Netherlands, discovered the spontaneous asymmetric synthesis method.

"The first left-handed amino acids could have been produced in this way, no matter whether this happened on earth or somewhere else in the universe," Rene says.

The method used was invented a few years ago at Radboud University where crystals are allowed to repeatedly dissolve and grow through continuous grinding and stirring. All this does is accelerate the process, but if you have enough time – as you do during evolution – it will work without using this trick, says the team.

Reason for handedness
Why life is based on right-handed DNA and left handed amino acids has been a puzzle for long.

Recent research suggests that electrons in cosmic rays -- which are mostly left-handed -- preferentially destroyed left-handed precursors of DNA on primordial Earth.

Interestingly, if the bias toward left-handedness in amino acids originated in space, it makes the search for extraterrestrial life in our solar system more difficult, while also making its origin a bit more likely, according to Nasa.

The Philae lander in ESA's comet mission was commissioned to look for clues to the single-handedness of organic molecules.