A semi-synthetic organism with an expanded genetic alphabet

Triphosphates of hydrophobic nucleotides d5SICS and dNaM are imported into Escherichia coli by an exogenous algal nucleotide triphosphate transporter and then used by an endogenous polymerase to replicate, and faithfully maintain over many generations of growth, a plasmid containing the d5SICS–dNaM unnatural base pair.