A Limit to Evolution? Where Is Their Imagination?

Why do we only see twenty amino acids in life? While there are a couple of lesser-known amino acids used (selenocysteine and pyrrolysine), those follow special pathways that don't use the genetic code. Hundreds of amino acid forms exist, yet life universally uses the same subset of twenty. Here's a contest for the explanatory power of design over evolution.

In Science Advances (the open-access publishing arm of the AAAS), evolutionists from Spain tackled this question with a new proposal: th...