A new theory that explains why the language of our genes is more complex than it needs to be also suggests that the primordial soup where life began on earth was hot and not cold, as many scientists believe.
…
The University of Bath researchers suggest that the primordial ‘doublet’ code was read in threes - but with only either the first two ‘prefix’ or last two ‘suffix’ pairs of bases being actively read.

By combining arrangements of these doublet codes together, the scientists can replicate the table of amino acids - explaining why some amino acids can be translated from groups of 2, 4 or 6 codons. They can also show how the groups of water loving (hydrophilic) and water-hating (hydrophobic) amino acids emerge naturally in the table, evolving from overlapping ‘prefix’ and ‘suffix’ codons.

The University of Bath researchers suggest that the primordial ‘doublet’ code was read in threes - but with only either the first two ‘prefix’ or last two ‘suffix’ pairs of bases being actively read.

By combining arrangements of these doublet codes together, the scientists can replicate the table of amino acids - explaining why some amino acids can be translated from groups of 2, 4 or 6 codons. They can also show how the groups of water loving (hydrophilic) and water-hating (hydrophobic) amino acids emerge naturally in the table, evolving from overlapping ‘prefix’ and ‘suffix’ codons.
…
The theory also explains how the structure of the genetic code maximises error tolerance. For instance, ‘slippage’ in the translation process tends to produce another amino acid with the same characteristics, and explains why the DNA code is so good at maintaining its integrity.

“This is important because these kinds of mistakes can be fatal for an organism,” said Dr van den Elsen. “None of the older theories can explain how this error tolerant structure might have arisen.”