Amino Acids And Life

Amino acids are the building blocks of proteins, which are, in turn, the building blocks of life. On Earth, all life uses only 20 amino acids, even though there are hundreds found in nature. Scientists have long wondered how only the 20 found their way into living molecules, and whether other amino acids could play a part in life elsewhere.

A new study suggests the 20 amino acids in Earth life are there because they functioned slightly better in the primordial environment than other combinations of acids. Natural selection, then, shaped Earthly biology even before there was Earthly biology.

This suggests that life on an Earth-like world elsewhere could be made of the same stuff we are, right down to the amino acids. On the other hand, a slightly different environment at the beginning could result in life forms that use a different mix of amino acids.