Clue 1: Orient yourself
What are the main parts, stages, or choices in this model?
Use the labels and the picture's left-to-right, near-to-far, or before-and-after order. Name only what you can point to.
The question
How could a scientist find one exact typo inside a huge instruction book and test a repair?
Why it matters: Genome editing can make a permanent DNA change. Researchers must confirm that the intended site changed, that enough cells changed, and that important off-target sites did not.
On your WebXam
You can use a find-cut-repair model to explain a targeted gene change and why the result must be checked.
For life
Having a gene is not the same as using it.
Principle: Having it is not using it
Try the everyday version first
Having it is not using it
A precision editor finds one marked shape on a page, changes it, and sends the revised page through several checks. Each check asks whether the intended mark changed and whether anything else changed by mistake.
Do not jump to the biology yet. Treat the picture as a small system. Track its parts, follow one change at a time, and keep more than one explanation open until the picture supplies a way to separate them.
Clue 2: Trace one change
What changes while the other parts stay the same?
Follow one object, stage, or path. Point to the first place where the situation changes instead of jumping to the ending.
Clue 3: Keep the cause open
What check would separate two explanations that still fit the picture?
List more than one explanation that still fits. Name the extra observation that would help you separate those possibilities.
Now inspect the illustration
Work from the visible evidence. A useful answer names the part of the picture that supports it and leaves unknown causes open.
- 1What are the main parts, stages, or choices in this model?
- 2What changes while the other parts stay the same?
- 3What check would separate two explanations that still fit the picture?
Tier 1 check
Finish with the everyday model
Describe the find, change, and check steps for correcting one exact mark without changing the rest of the page.
Answer in plain words. You can finish this required check without opening either optional section below.
Ready for the real names? Optional tier 2
Craniofacial Research Track
Session 14The Fix, January (intensive)Lens: Genetics of Disease
CRISPR-Cas9: programmable molecular scissors
Discovery question
How could a scientist find one exact typo inside a huge instruction book and test a repair?
Having it is not using it. Rewriting an instruction changes what a cell could build, but the change matters only if it reaches the right cells and is used at the right time.
Before this page, you should know
- ClinVar is a public archive of reported genetic variants and what they mean for health.
- A is classified as disease-causing; a has an unknown effect.
If not, review
Today's new idea is only
Having it is not using it. Rewriting an instruction changes what a cell could build, but the change matters only if it reaches the right cells and is used at the right time.
Goal: Use the find-cut-repair model to explain how one planned instruction change is made and why the result must be checked.
Know by the end
- A guide RNA is a short RNA written to match a chosen target by base pairing.
- Cas9 is the that does the cutting; the guide RNA steers it to the right spot.
- Cas9 makes a cut in the DNA, and the cell then repairs that cut.
- If a healthy template is supplied during repair, the cell can copy it and the sequence is changed back toward the healthy version (gene correction).
- is programmable: change the guide RNA and you change the target, without changing the Cas9 .
1
The three parts
Model start: The guide RNA is a short RNA whose letters match the target DNA, so it finds and binds the one spot we chose.
- Label a simple diagram with the three parts: the target DNA, the guide RNA, and the Cas9 .
- In one sentence each, write the job of the guide RNA and the job of Cas9.
2
Find, cut, repair
Model start: First the guide RNA binds the matching DNA site, then Cas9 cuts at that spot, then the cell repairs the cut.
- Put these steps in order: Cas9 cuts the DNA, the guide RNA binds the matching site, the cell repairs the cut.
- Explain why we say is programmable, using the words guide RNA and target.
3
From a cut to a correction
Model start: Gene correction means repairing a disease-causing DNA change back toward the healthy sequence; here that is the IRF6 change behind Mateo's .
- A cut by itself is not a fix. Explain what has to be supplied so the cell repairs toward the healthy sequence.
- Connect this to Mateo: which gene change from Phase 3 would a correction aim to repair?
MedlinePlus
Open the tool Plain-language explanations of a gene or condition, written for patients and families.
When you use this: Use this when a research paper is too dense, or when you need to explain a finding to Mateo's family in everyday words.
What the screen looks like
Step by step
- 1Open medlineplus.gov/genetics and search the gene or condition (IRF6).
- 2Read the summary written in everyday words.
- 3Note the conditions the gene is linked to at the bottom of the page.
Capture these fields
- Topic: IRF6 gene
- Plain-language summary: IRF6 helps the tissues of the face join correctly before birth.
- Linked conditions: Van der Woude syndrome; nonsyndromic cleft
How to read it: Start here when a research paper is too dense. MedlinePlus gives you the gist in everyday words so you can go back to the harder source knowing what it is about.
Lost? About MedlinePlus Genetics
Level 1, Guided
Use the sentence starters, a word bank from the vocabulary, a labeled diagram, and the exact source link.
Level 2, Collaborative
Complete a partly blank model or table and explain it.
Level 3, Independent
Make a claim from a new example or an unfamiliar entry in the same database.
Team roles
- Manager: keeps the group moving
- Recorder: writes the shared model or table
- Evidence checker: verifies each claim against the source
- Reporter: explains the group's reasoning
Process reflection
- What evidence changed your thinking today?
- What did your group disagree about, and how did you resolve it?
- What question is still unresolved?
By the end of this session, submit ONE of: a labeled diagram with a 2-sentence explanation; a claim, evidence, reasoning paragraph; a completed data table from a real database; or a one-question exit ticket using today's vocabulary.
Meets standard if your explanation correctly connects structure, timing, gene or protein function, or evidence source to Mateo's case: Use the find-cut-repair model to explain how one planned instruction change is made and why the result must be checked.
How this is graded (rubric)
For: Use the find-cut-repair model to explain how one planned instruction change is made and why the result must be checked.
| 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. |
How the model answer scores against this rubric
- CompleteProficient: Nothing is left blank: the model fills every part of "Use the find-cut-repair model to explain how one planned instruction change is made and why the result must be checked.".
- 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.
Go deeper Optional tier 3
Everything required is above. Open this section only if you want the research reading and source trail.
Student reading
The idea in plain English
How could a scientist find one exact typo inside a huge instruction book and test a repair?
A precision editor finds one marked shape on a page, changes it, and sends the revised page through several checks. Each check asks whether the intended mark changed and whether anything else changed by mistake.
Having it is not using it. Rewriting an instruction changes what a cell could build, but the change matters only if it reaches the right cells and is used at the right time.
- A guide RNA is a short RNA written to match a chosen target by base pairing.
- Cas9 is the that does the cutting; the guide RNA steers it to the right spot.
- Cas9 makes a cut in the DNA, and the cell then repairs that cut.
- If a healthy template is supplied during repair, the cell can copy it and the sequence is changed back toward the healthy version (gene correction).
- is programmable: change the guide RNA and you change the target, without changing the Cas9 .
This lesson reading is written from the vetted sources in the advanced citation trail below.
Everything you need for today is on this page. These links are optional.
What to read
Read the short plain-language explanation written for this lesson. Plain-language reading for this session
Why this source matters
This explanation gives you the background for today's idea without making you decode a research paper: Having it is not using it. Rewriting an instruction changes what a cell could build, but the change matters only if it reaches the right cells and is used at the right time.
Words to unlock first
Reading moves
- 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.
Stop point
Stop after the final 'Use it now' section. The research citations are available separately for advanced readers.
Your output
Write one claim-evidence sentence: state the main idea, then name the example or evidence that supports it.
These records and papers document the science. They are not assigned student reading. Use the plain-language lesson reading above unless your teacher asks you to inspect an original source.