Compare two BLAST hits: E-value and query coverage
Tue, Sep 15, 2026 · Week 4 · Genetics of Disease (Medical Interventions)
Today's goal: Compare two recorded hits using percent identity, E-value and query coverage, then write a qualified statement that matches the evidence.
Illustrative practice values, not a BLAST run or case result. This completes the local comparison-practice product only. It does not record a successful search, finish the missing Monday activity or certify official PLTW completion.
Illustrative practice values, not a BLAST run or case result. In the same illustrative comparison context, A and B both have 99% identity. A has greater query coverage (98% versus 11%) and a smaller E-value (2e-60 versus 0.4), supporting a stronger reported sequence-similarity comparison for A. This does not establish an organism's identity, a diagnosis or a disease cause.
| Hit label | Percent identity | E-value | Query coverage |
|---|---|---|---|
| A | 99% | 2e-60 | 98% |
| B | 99% | 0.4 | 11% |
This model shows the level of evidence and organization needed to complete: One two-hit comparison table and a revised, qualified statement citing percent identity, E-value and query coverage.
- Choose two usable hits from your saved Monday record. If unavailable, use the supplied A/B illustrative practice and label that route. Keep the actual missing or unfinished step noted separately in the same record.
- Read the definitions of query, hit, percent identity, query coverage and E-value. Use the notation aid before copying a small E-value.
- Fill both rows of the comparison table from the chosen evidence. Keep the source and context with the actual column labels. Do not invent a missing value.
- Compare percent identity, query coverage and E-value together. Explain what the recorded measures support. If the measures conflict or information is missing, state the uncertainty instead of forcing a winner.
- Revise the statement so it cites all three recorded measures and stays within the claim limit. Keep illustrative practice separate from an actual search result.
- Check the two rows, source label and statement. Submit one PDF through assignment 8520302476, unless your paper was collected in class. Keep the record for later work.
This completes the local comparison-practice product only. It does not record a successful search, finish the missing Monday activity or certify official PLTW completion.
Submit the table and revised statement together as one PDF to Schoology assignment 8520302476 by Tuesday, September 15 at 11:59 PM. If your paper was collected in class, do not upload it again. Keep your original record.
Two-hit comparison: one PDFClaim ceiling: The comparison cannot establish an organism's identity, a diagnosis or a disease cause.
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.
| Hit label | Percent identity | E-value | Query coverage |
|---|---|---|---|
| A | 99% | 2e-60 | 98% |
| B | 99% | 0.4 | 11% |
Tap an answer to see the full explanation. Nothing is recorded or graded.
It builds this reusable test skill: Reading comparison measures without overclaiming.
- 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.