Venn Diagram of Amino Acids.
<a href="//commons.wikimedia.org/wiki/User:Hoffmeier" title="User:Hoffmeier">Klaus Hoffmeier</a>
adapted from: Taylor WR. (1986): The classification of amino acid conservation. J Theor Biol. 119(2):205-18. <a class="external mw-magiclink-pmid" rel="nofollow" href="//www.ncbi.nlm.nih.gov/pubmed/3461222?dopt=Abstract">PMID 3461222</a>