• Once information is in protein, cannot be retrieved

Can do this:

           ┌───────────┐
           │           ▼
DNA ────▶︎ RNA ────▶︎ Protein
 │                     ▲
 └─────────────────────┘

But not this:

 ┌────────┐ ┌──────────┐
 ▼        │ ▼          │
DNA       RNA       Protein
 ▲                     │
 └─────────────────────┘