guanine /ˈɡwɑː.niːn/ noun1 •A substance first obtained from guano; it is a nucleic base and pairs with cytosine in DNA and RNA (by means of three hydrogen bonds).Then he found them, the substances that made up the four-letter alphabet in whose language all life is written — adenine and cytosine, guanine and thymine. — 1997 formsguanines
