Researchers used mixtures of both left- and right-handed aspartic acid (an amino acid) in laboratory experiments to see how temperature and other conditions affected formation of crystals of the material.
They found that under conditions that could have existed on primitive Earth, left-handed aspartic acid crystals could have formed easily and on a large scale. "The aspartic acid crystal would then truly become a single mother crystal: an ancestral Eve for the whole left-handed population," the article notes.
Molecules of aspartic acid with a left-handed orientation, in crystal form, could be the "ancestral Eve" of all amino acids -- the building blocks of proteins -- in life on Earth.(Photo Credit: American Chemical Society)
The authors point out that conditions on the primordial Earth held an equal chance of forming the same amounts of left-handed and right-handed amino acids. Nevertheless, when the first forms of life emerged more than 3 billion years ago, all the amino acids in the proteins had the left-handed configuration. That pattern continued right up to modern plants and animals.
Citation: Tu Lee, Yu Kun Lin, 'The Origin of Life and the Crystallization of Aspartic Acid in Water', Crystal Growth&Design, 2010; 10(4), 1652; doi: 10.1021/cg901219f