Clue 1: Orient yourself
Which edit changes one item but keeps the rest?
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
Which edit changes one item but keeps the rest?
Why it matters: Genetic results can change family counseling and research decisions. They must be interpreted without turning risk into destiny or an uncertain variant into a diagnosis. Today you practice the professional reasoning behind that work: DNA variants change proteins in different ways, so variant type is evidence about mechanism, not a verdict by itself.
On your WebXam
Classifying a DNA change by type and predicting its effect on the protein
For life
To find the cause, change one thing and watch what changes.
Principle: Same look, different cause
Five principles we return to
Having it is not using it
Same instructions, different switches
Same look, different cause
Change one thing and watch
Boss or doorman?
Decides the result or only allows it
Held down, not gone
Remove the brake and it returns
Many roads, one ending
One result can begin many ways
Try the everyday version first
Edit one instruction manual four different ways
An instruction manual can change through a replaced word, a missing line, an added line, or a changed stop signal. Different edits can alter one step or everything that follows.
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
Which edit stops the message early?
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
Which edit shifts every group after it?
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.
- 1Which edit changes one item but keeps the rest?
- 2Which edit stops the message early?
- 3Which edit shifts every group after it?
Tier 1 check
Finish with the everyday model
Use the everyday picture to answer today's question in plain words: Which edit changes one item but keeps the rest?
You can complete today's required check without opening the technical details below.
Ready for the real names? Optional tier 2
Technical rules and limits
Rule 1: Missense swaps one amino acid.
Rule 2: Nonsense and frameshift variants can truncate protein.
Rule 3: Splice variants can change which RNA sections remain.
Where the analogy stops: Protein consequences depend on location and biology, not only the editing label.
Carry the previous idea forward
Variant interpretation combines clinical assertions, population frequency, molecular consequence, and evidence quality.
Today's technical takeaway
DNA variants change proteins in different ways, so variant type is evidence about mechanism, not a verdict by itself.
Now map the same rules onto biology
Translate four IRF6 variant types
Swapped word
Missense variant
Early period
Nonsense variant
Shifted spacing or page join
Frameshift or splice-site variant
Educational illustration, not a clinical photograph or diagnostic result. Use the labeled evidence cards and claim ceiling.
Mateo's case file: evidence supplied in this lesson
GEN07-E1
A missense variant replaces one amino acid.
Why it matters: The rest of the reading frame can remain intact.
GEN07-E2
A nonsense or frameshift variant can create a premature stop.
Why it matters: The protein may be shortened or its RNA degraded.
GEN07-E3
A splice-site variant can alter exon joining.
Why it matters: The mature mRNA can lose or gain sequence.
Make the clinical decision
You are annotating three IRF6 lab reports.
Report A is missense, B is an early nonsense, and C is a splice-site change near an exon boundary.
APredict different possible consequences and request location-specific evidence.
BCall all three identical.
CCall every missense benign.
Choose the annotation strategy and cite two distinct mechanisms.
Evidence required
GEN07-E1 + GEN07-E2 Claim ceiling
You may predict molecular consequences. You may not classify pathogenicity from variant type alone.Go deeper Optional tier 3
Everything required for today is above. Open these only if you want the explainer, source trail, or download files.
The everyday model and Tier 1 check are the complete required path for this lesson.
Use these checks to keep your place. They are not turned in through the portal.
Check off as you finish
- Worked through the everyday picture and answered its three questions.
- Completed the Tier 1 check in plain words.
Turn in: Genetics lesson 7: Kinds of Typos in DNA
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Optional legacy technical materials Open only if you want the original notes, vocabulary, artifact, and CER work
Before this page, you should know
- DNA is read three letters at a time as codons.
- IRF6's must keep its shape to bind DNA and do its job.
If not, review
Today's new idea is only
Today's new idea is only this: the KIND of typo (, , , or splice) predicts how much of the survives.
Goal: Students will classify a DNA change as , , , or splice from a sequence and predict its effect on the .
Know by the end
- DNA is read three letters at a time as codons; the run of codons is the .
- A change swaps one amino acid; the stays full length but may be altered.
- A change creates a premature stop codon, cutting the short; a ( or deletion not a multiple of 3) scrambles everything .
- A splice-site change at an intron/exon boundary causes wrong joining of the mRNA.
1
Reading frame and codons
Model start: DNA is read three letters at a time in codons; the run of codons is the .
- DNA is read in three-letter codons, and the run of codons is the reading ____.
- Each codon names one amino acid or says stop.
2
The four typo types
- : one base change swaps one ____ for another; the is full length but may be altered (example IRF6 R84C).
- : a base change creates an early ____ codon; the is cut short (example IRF6 R250X).
- : an or deletion NOT a multiple of ____ shifts the ; splice-site: a change at an intron/exon boundary so mRNA pieces are joined ____.
3
The big pattern
- and typos are truncating and usually destroy most of the from that copy.
- A leaves a full-length that may work, partly work, or actively misbehave.
Everything you need for today is on this page. These links are optional.
What to read
Skim the variant tables in Leslie et al. (2012) just to see the variant codes (like R84C and R250X); you only need to recognize the format, not memorize them. Leslie EJ, et al. 2012. IRF6 variants in VWS and PPS. Genet Med. [PMID:23154523]
Why this source matters
These are the real IRF6 typo codes; learning to read them is how you tell a one-amino-acid swap from a cut short in Mateo's gene.
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
You do not need to understand the clinical details or the statistics. Just learn what the variant codes mean.
Your output
Write one claim-evidence sentence: which kind of typo leaves a full-length , and which removes part of it.
Where this fits
Tested on (Ohio WebXam)
Genetics of Disease · 072130
PLTW lesson
MI · Genetics domain · Unit 2 How to Screen Your Genes, 2.1 Genetic Testing and Screening
WebXam domain
Molecular and Genetic Technology
Evidence to produce
Classify three IRF6 codes (R84H, R412X, and a single-base deletion in exon 4) as missense, nonsense, frameshift, or splice, and for each state whether the protein is likely full-length-but-altered or truncated.
Lab / skill
Medical Interventions (MI) · Principles of Biomedical Science (PBS)
Everything required for today's decision is already in the case file and plain-language explainer. The links below are original papers and database records for teachers and advanced readers, not assigned student reading.
How this is graded (rubric)
For: Classify three IRF6 codes (R84H, R412X, and a single-base deletion in exon 4) as missense, nonsense, frameshift, or splice, and for each state whether the protein is likely full-length-but-altered or truncated.
| 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 "Classify three IRF6 codes (R84H, R412X, and a single-base deletion in exon 4) as missense, nonsense, frameshift, or splice, and for each state whether the protein is likely full-length-but-altered or truncated.".
- 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.
What's next: We can sort IRF6 typos by type. But IRF6 causes two different diseases, a milder one and a more severe one. Why would one gene cause two diseases?