How Do We Prove the Gene Causes It?
Genetics domain · Lesson 15 of 20 · Medical Interventions (MI), with PBS overlap
Today's goal: Use the logic of model-organism knockouts and rescue experiments to argue that IRF6 loss causes clefting rather than merely correlating with it.
This is a model of the work you should turn in. Use it to check your own: match the structure and the level of detail, do not copy it. Your wording should be your own.
Reply, part 1 (what is missing): Having an IRF6 variant and a cleft at the same time is only correlation: two things observed together. By itself it cannot prove IRF6 caused the cleft, because something else could explain both.
Reply, part 2 (the test): To show causation, use a model organism. First knock out IRF6 in a mouse or zebrafish and check whether a cleft appears; it does in both. Then do the rescue: put IRF6 back (irf6 mRNA in zebrafish, an Irf6 transgene in mouse) and check whether the cleft is corrected. In zebrafish the cleft was rescued and esrp1 returned; in mouse the rescue was partial. Because removing the gene broke the process and restoring it fixed it, IRF6 is a cause, not just a bystander.
This model shows the level of evidence and organization needed to complete: A two-part rebuttal that names the missing experimental step and designs the test that would supply it.
- Write one defensible claim.
- Choose specific evidence that supports the claim.
- Explain the scientific rule that connects the evidence to the claim.
Keep the structure. Replace the question, facts, measurements, and evidence. Then recheck units, vocabulary, and whether the conclusion goes beyond the evidence.
The finished product above did not appear all at once. Here is the path from the question to the turned-in work, so you can follow the same steps.
- 1Start from today's question: How can scientists show that one changed instruction caused a problem instead of just being there too?
- 2Work the Model and the Explore questions to reason it out before writing anything.
- 3Pull the specific evidence the product needs from the reading and any database you used.
- 4Write it up in the required format: A classmate argues: "Mateo has an IRF6 variant and a , so IRF6 must cause his cleft." As the model researcher, write a two-part reply: (1) name what is missing from that argument (correlation vs causation), and (2) describe the -then- in an animal that would actually test it.
- 5Check it against the rubric, then submit.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in through the route named under Submit here and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
- CompleteProficient: Nothing is left blank: the model fills every part of "A classmate argues: "Mateo has an IRF6 variant and a cleft, so IRF6 must cause his cleft." As the model researcher, write a two-part reply: (1) name what is missing from that argument (correlation vs causation), and (2) describe the knockout-then-rescue experiment in an animal that would actually test it.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be attached to your class form or handed in, and confirmed.
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Distinguishing correlation from causation using knockout and rescue logic.
- Name the concept or data pattern being tested.
- Cross out choices that violate that rule or the evidence.
- Justify the best remaining choice before checking the answer.