letter by letter

While famous techniques enable changes to be made letter by letter, some engineering tasks are more efficient if researchers build DNA from scratch, with far-flung changes made in large swaths of pre-assembled code swapped into a cell in place of its natural counterpart.

The RNA polymerases move along these strands and copy the stored information letter by letter.

The children and parents held signs that spelled out — letter by letter — a newish slogan for Youngkin: “Compete to Win.”

In fact, functional magnetic resonance imaging of the brain demonstrates that humans process written language letter by letter, sound by sound.

One morning, before he roused Mr. Kugler with cake and coffee, he spelled out “Will you marry me?” letter by letter on individual Post-its and stuck each to a mirror.