Somewhere in a sample of ordinary pond water, a single-celled organism has been quietly breaking one of biology’s most fundamental rules. Condylostoma magnum, a free-living ciliate barely visible to ...

The genetic building blocks of life—formed from the four nucleotides adenine (A), cytosine (C), guanine (G), and thymine (T)—are read in groups of three known as codons. While some codons (known as ...