The major nucleotides
<a href="//commons.wikimedia.org/wiki/User_talk:BorisTM" title="User talk:BorisTM">Boris</a> (PNG), SVG by <a href="//commons.wikimedia.org/wiki/User:Sjef" title="User:Sjef">Sjef</a>
<a href="https://en.wikipedia.org/wiki/Image:Nucleotides.png" class="extiw" title="en:Image:Nucleotides.png">en:Image:Nucleotides.png</a>