Safety, privacy and evidence boundary
Use fictional DNA/RNA/protein sequences and standard codon tables. Do not use personal genomic data or infer disease from sequence examples. Sequence exercises are educational models, not clinical interpretation.
Explicit science instruction
Many eukaryotic primary transcripts are processed before translation. A 5′ cap and poly(A) tail affect stability and translation; splicing removes introns and joins exons. Alternative splicing can produce multiple mature RNA isoforms from one gene.
Processing is regulated and context dependent; “one gene = one protein” is therefore an oversimplification.
Worked example with reasoning
Primary transcript exons E1-E2-E3 with introns between them might yield mature E1-E2-E3 or, in an alternative isoform, E1-E3 if E2 is skipped. The DNA locus is unchanged; the RNA processing outcome differs.
Guided question
How can one DNA locus contribute to more than one protein product?
Independent work
- Mark introns/exons on a fictional transcript.
- Create two splice isoforms.
- Predict how an exon skip could alter a protein.
- State one limit of the simplified cartoon.
Misconception check
Introns are not simply “junk,” and alternative splicing does not mean cells randomly cut RNA without regulation.
Formative understanding check
Does alternative splicing require changing the DNA sequence?
Worked response
No. Different RNA segments can be joined from the same underlying gene.
Open-book formative practice only; not an official mastery attempt or grade.
Mentor evidence conference
Ask Archaemenes to challenge your information-flow model, sequence reasoning, data interpretation, and limitations.
Open ArchaemenesTeacher guidance
Foundation: use cut-and-join paper exons. Core: explain processing and isoform consequences. Extended: connect splice-site regulation to tissue-specific expression conceptually.
Preserve learning evidence
Keep sequence work, models, corrections, and limitations in the matching Week 24 evidence field.