This packet is everything a parent or guide needs to assess Unit 06 at home — learning targets, the answers that count as correct, the mastery rubric, calibration examples, and a clipboard score sheet. No multiple-choice test: the student shows mastery by reading a worked STR profile, making a disciplined comparison, and reporting a match with its random-match probability.
By the end of the DNA & Biological Evidence unit, a student should be able to:
Six criteria, each judged Not yet / Approaching / Mastered (Page 3).
Read a worked STR profile; make a disciplined comparison.
The student reports a match with its random-match probability (Page 4).
Profile, comparison, and match statistic kept distinct.
You are making a decision, not adding up points. For each criterion, decide whether the work is Not yet, Approaching, or Mastered — the column language tells you which. A criterion counts as mastered only when the student can both read the profile and report the match honestly. A student carries three tokens per term; one token buys a re-do of one criterion on another day, so a single bad afternoon never sinks the unit.
Accept any answer in the synonyms column — they are pre-approved as equivalent. The third column flags the confusions that look close but are not yet, so you can coach precisely.
| Canonical answer | Accepted synonyms | Common confusion / discriminator |
|---|---|---|
| Profile & method | ||
| DNA profile | STR profile | A set of STR marker values; distinguishes people, is not a picture of the whole genome |
| STR (short tandem repeat) | STR locus | A region repeated a variable number of times; the count differs between people |
| PCR amplification | polymerase chain reaction | Copies tiny amounts of DNA so a profile can be read; amplifies, does not compare |
| Gel electrophoresis | capillary electrophoresis | Separates DNA fragments by size; the separation step, not the copying |
| Reading & reporting | ||
| Random-match probability | RMP | The chance a random person shares the profile; a statistic, never 100% |
| Prosecutor's fallacy | transposed conditional | Confusing “rare profile” with “probably guilty” — the error to avoid |
| Contamination / degradation | sample compromise | Foreign or broken-down DNA; limits what the profile can support |
| Reference / exemplar sample | known sample | A known-source sample compared against the questioned profile |
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| DNA structure & STR profiling | Cannot explain why DNA differs between people. | Describes DNA structure but not why STR regions individualize. | Explains how variation at STR loci lets a profile distinguish one person from nearly everyone else. |
| Extraction, PCR & electrophoresis | Cannot outline how a sample becomes a profile. | Names the steps but confuses amplification with separation. | Explains extraction, PCR amplification, and gel electrophoresis as concepts and what each contributes to a profile. |
| Reading a profile & comparison | Cannot read the peaks or lanes on a profile. | Reads a profile but compares it loosely or over-reads a partial. | Reads a profile and makes a disciplined comparison, stating clearly whether loci are included, excluded, or inconclusive. |
| Match probability & statistics | Calls a match a certainty or commits the prosecutor's fallacy. | Cites a random-match probability but slips into stating it proves identity. | Interprets the random-match probability correctly, avoids the prosecutor's fallacy, and reports a match as a statistic — never as 100% or as proof of guilt. |
| Sample integrity | Ignores contamination, degradation, or partial profiles. | Notices a problem sample but draws firm conclusions anyway. | Recognizes contamination, degradation, and partial or absent profiles, and limits conclusions to what the sample supports. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
The split between Approaching and Mastered is honest statistics: a strong random-match probability is a strong association, not proof of identity or guilt. Ask “what does the statistic say — and what does it not?”
Read these before you grade. They show what Mastered and Not yet actually sound like, plus the edge cases where you should coach rather than decide on the spot.
Student: ______________________________________ Date: _______________ Guide: _________________________
| # | Criterion | Decision | Notes |
|---|---|---|---|
| 1 | DNA structure & STR profiling | NY / Appr / Mast | |
| 2 | Extraction, PCR & electrophoresis | NY / Appr / Mast | |
| 3 | Reading a profile & comparison | NY / Appr / Mast | |
| 4 | Match probability & statistics | NY / Appr / Mast | |
| 5 | Sample integrity | NY / Appr / Mast | |
| 6 | Integration (cross-domain) | NY / Appr / Mast |
☐ No ☐ Yes — for criterion: __________ Tokens remaining: ☐ 3 ☐ 2 ☐ 1 ☐ 0
NY = Not yet · Appr = Approaching · Mast = Mastered · Unsure between two levels? Circle the lower one and note what a re-do would need.