meanwhile, back in the lab

While Dembksi et al. attempt to play down Harvard's origin-of-life research project, actual scientists continue making progress toward understanding the origin of life. Surprise: DNA is redundantly complex.

One of quirks of the genetic code is that there are groups of codons which all translate to the same amino acid. For example, the amino acid leucine can be translated from six different codons whilst some amino acids, which have equally important functions and are translated in the same amount, have just one.

The new theory builds on an original idea suggested by Francis Crick - one of the discoverers of the structure of DNA - that the three-letter code evolved from a simpler two-letter code, although Crick thought the difference in number was simply an accident “frozen in time”.

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.

As NewScientist reports, the new theory is a plausible explanation for the rise of a triplet code, but not the only candidate, and that Van den Elsen plans to scan multivarious genomes in search of "ancient genes that can be read using the older, doublet codes."

Oh, and check out Astrobiology Magazine for even more advances in OOL research.