This work was supported by the National Institutes of Health (GM118178 to F.E.R.);
the National Science Foundation Graduate Research Fellowship (DGE-1346837 to A.W.F.) and the Boehringer Ingelheim Fonds Ph.D. Fellowship program (E.C.F.). We thank Synthorx Inc. for providing unnatural triphosphates and oligonucleotides.This work was supported by the National Institutes of Health (GM118178 to F.E.R.);
the National Science Foundation Graduate Research Fellowship (DGE-1346837 to A.W.F.);
and the Boehringer Ingelheim Fonds Ph.D. Fellowship program (E.C.F.). We thank Synthorx Inc. for providing unnatural triphosphates and oligonucleotides;