Knock It Out, Then Put It Back: Proving a Gene Causes a Defect
Take the reading one piece at a time. For each piece: read it once, underline the sentence that says what happens, then look up any word in the list. Tap a word to see its definition.
Piece 1 of 2
In the Ezh2 palate study, deleting Ezh2 in the palate lining produced clefts in about 20% of mice. A skeptic could say a backup gene normally covers for Ezh2, so the result is really about that backup. Ezh2 has a sister gene, Ezh1. The team also deleted Ezh1. On its own, losing Ezh1 did nothing to the palate; it was dispensable. That extra knockout ruled out the backup-gene story.
Piece 2 of 2
Now think about two separate questions you could ask about any part. If I remove the part, does the machine break (is the part needed)? If I put the part back, does the machine work again (was that part the fix)? A famous developmental example uses TGF-beta3 (Tgfb3): delete it and mouse palate shelves touch but cannot fuse, leaving a cleft; re-supply that same TGF-beta3 signal and the shelves fuse again. Removing it breaks fusion; adding it back restores fusion.
Reading the Research
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Now put it together: In one or two sentences, say what this whole reading is telling you about Mateo. Then go back to the lesson and fill in the guided notes.