The clip The facts of life from Blade Runner (1982) with Joe Turkel, Rutger Hauer
The facts of life.
To make an alteration in the evolvement of an organic life system is fatal.
A coding sequence cannot be revised once it's been established.
Because by the second day of incubation any cells that have undergone reversion mutations give rise to revertant colonies like rats leaving a sinking ship.
Then the ship sinks.
What about EMS recombination?
We've already tried it.
Ethyl methane sulfonate is an alkylating agent and a potent mutagen.
It created a virus so lethal the subject was dead before he left the table.
Then a repressor protein that blocks the operating cells.
Wouldn't obstruct replication, but it does give rise to an error in replication.
So that the newly formed DNA strand carries a mutation and you've got a virus again.
But this, all of this, is academic.
You were made as well as we could make you.
But not to last.
The light that burns twice as bright burns half as long.
And you have burned so very, very brightly, Roy.
Look at you.