E-value and query coverage
Interpret E-value and query coverage to judge how trustworthy a BLAST match really is.
Two-hit comparison table (E-value, query coverage, percent identity) and revised identification statement citing all three metrics.
- 1Do thisInterpret E-value and query coverage to judge how trustworthy a BLAST match really is.
- 2Use this resource
- 3Submit thisData table: Two-hit comparison table (E-value, query coverage, percent identity) and revised identification statement citing all three metrics.
- 4Submit it here
- 1CMSD website. Go to clevelandmetroschools.org and click the Clever button.
- 2Clever. Clever opens. Sign in if it asks.
- 3Microsoft (district) login. Use your district Microsoft account (the one for school).
- 4Schoology. Open Schoology, then your class, then Assignments, and find the file named below.
The file to submit is named: Genetics of Disease (Medical Interventions) › DNA identification, sequencing, BLAST, controls, query coverage, and E-value. › Data tableOpen Schoology
- CER:
- Claim, Evidence, Reasoning — make a claim, back it with evidence, explain your reasoning.
- SOP:
- Standard Operating Procedure — the exact steps to follow (especially in a lab).
- Tracker:
- Your PLTW progress log where you record completed evidence.
- myPLTW:
- The PLTW course site where you do the online activities — you open it through Schoology.
Minute-by-minute · 80-minute block
💡 Big idea: What makes one database match more trustworthy than another with equal percent identity?
- 0-10 minReopen Wednesday's BLAST results; find and label E-value, query coverage, and percent identity for the top hit
- 10-25 minWrite plain definitions of E-value and query coverage in your notebook
- 25-40 minCompare two hits from the results: rank them using all three numbers and explain which is stronger and why
- 40-55 minFlag any hit with high identity but low coverage; write one sentence explaining the reliability risk
- 55-70 minRevise your pathogen identification statement to cite E-value, query coverage, and percent identity
- 70-80 minShare revised statement with a partner; check that all three numbers are cited correctly
- • Percent identity alone can fool you: a 99% match over 10 bases is meaningless; a 95% match over the full sequence is strong.
- • E-value and query coverage are the two numbers scientists use to decide if a match is real or just statistical noise.
- • Today you apply these criteria to your Wednesday results and revise your identification with quantitative support.
- • Exit goal: a revised identification statement citing all three match-quality numbers.
- 1Reopen your BLAST results and find the E-value and query coverage for your top hit.
- 2Write what each means: E-value as how likely the match is by chance, coverage as how much aligned.
- 3Compare two hits and decide which is stronger using both numbers.
- 4Note the rule: a smaller E-value and higher coverage mean a more reliable match.
- 5Flag any hit that looks high in identity but low in coverage and explain the risk.
- 6Revise your pathogen identification statement to cite E-value and coverage.
- • You will be able to explain what E-value and query coverage measure.
- • You will be able to rank two BLAST matches by reliability.
- • You will be able to support an identification with match-quality numbers.
- • E-value is the expected number of matches that random chance would produce; a smaller E-value means the match is less likely to be coincidence.
- • Query coverage tells you what fraction of your sequence was aligned; low coverage means only a short region matched, which is unreliable.
- • A trustworthy BLAST identification requires high percent identity, low E-value, AND high query coverage together.
Your PLTW work today
DNA identification, sequencing, BLAST, controls, query coverage, and E-value. · E-value and query coverage
Day 3 of this lesson. Open this exact section in myPLTW (reached through Schoology), then do the work below.
Do this: Reopen your BLAST results in myPLTW Activity 1.1.3 and focus on interpreting E-value and query coverage for your top hit.
Complete the two-hit comparison and write a revised identification statement citing E-value, query coverage, and percent identity.
BLAST screenshot should be done (Wednesday); revised identification statement due today.
Revised identification sentence in notebook citing all three metrics.
All PLTW activities are completed inside the PLTW course environment — this page only gives direction. Submit producibles on Schoology.
Today's PLTW tracker
Check things off as you work, then submit. This tells Mr. Mendoza how you're doing so he can help the class. It does not replace turning in your producible on Schoology.
Use the code Mr. Mendoza gave you, not your name. Saved on this device.
DNA identification, sequencing, BLAST, controls, query coverage, and E-value. · E-value and query coverage
Reopen your BLAST results in myPLTW Activity 1.1.3 and focus on interpreting E-value and query coverage for your top hit.
BLAST screenshot should be done (Wednesday); revised identification statement due today.
This is how Mr. Mendoza sees the class keeping pace with PLTW. Be honest, it only helps if it is accurate.
🎯 Interpret E-value and query coverage to judge how trustworthy a BLAST match really is.
- Reopen your BLAST results and find the E-value and query coverage for your top hit.
- Write what each means: E-value as how likely the match is by chance, coverage as how much aligned.
- Compare two hits and decide which is stronger using both numbers.
- Note the rule: a smaller E-value and higher coverage mean a more reliable match.
- Flag any hit that looks high in identity but low in coverage and explain the risk.
- Revise your pathogen identification statement to cite E-value and coverage.
Data table: Two-hit comparison table (E-value, query coverage, percent identity) and revised identification statement citing all three metrics.
Submit on SchoologyUpload by 11:29 PM for full credit.
| Task | Who |
|---|---|
| Reopen your BLAST results and find the E-value and query coverage for your top hit. | _______ |
| Write what each means: E-value as how likely the match is by chance, coverage as how much aligned. | _______ |
| Compare two hits and decide which is stronger using both numbers. | _______ |
| Note the rule: a smaller E-value and higher coverage mean a more reliable match. | _______ |
| Flag any hit that looks high in identity but low in coverage and explain the risk. | _______ |
| Revise your pathogen identification statement to cite E-value and coverage. | _______ |
Working solo? Put your own name in "Who" for every row.
- You will be able to explain what E-value and query coverage measure.
- You will be able to rank two BLAST matches by reliability.
- You will be able to support an identification with match-quality numbers.
Teacher-posted resources
Classroom documents for this lesson. Ones marked “Open the file” open right here; the rest are posted in Schoology. Use the label on each card to choose the right move.
Open this when the class reaches this activity and use it to complete the required lesson artifact.
Placement rationale
Matched Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/1.1_The-Mystery-Infection; keywords:blast, sequencing, pathogen, dna, identification. Score 162. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this after the required lesson work when you are ready for a harder application or a deeper connection.
Placement rationale
Matched Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/00_Unit-Overview; keywords:blast, pathogen, dna, identification. Score 150. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
Use this if you were absent, got stuck, or need another pass before you submit the lesson artifact.
Placement rationale
Matched Pathogen identification, PCR, sequencing, BLAST by path:Medical-Interventions/Unit-1_How-to-Fight-Infection/00_Unit-Overview; keywords:blast, pcr, pathogen, identification. Score 150. Visibility: student-schoology (student-facing resource; link through Schoology rather than local path).
How to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
Lab & supplies
This unit's vocabulary
Tap the speaker to hear a term. Weekly vocabulary task: add two of these terms to your notebook glossary with a definition and an example in your own words.
WebXam practice
Cumulative WebXam review
A quick mixed-review pulling questions from earlier units plus today, so the WebXam material stays fresh.
Where this leads — careers
What today's skills lead to. These are real health-science careers this course builds toward. Tap one to see, on the US Department of Labor's O*NET site, what the job actually involves, what it pays, and how fast it is growing.
What to do if you were absent
Today is individual PLTW work, so do exactly what we did in class, from home: complete the same PLTW target above, then submit your Data table.
Open Schoology (CMSD) and keep goingHow to get there: open the CMSD website, click Clever, sign in with your Microsoft (district) account, then open Schoology from Clever.
Class still runs. Complete the online activity above (it's self-guided). Need the concept taught without a teacher? Use this authoritative explainer:
NCBI BLAST- CompleteEvery required part of the artifact is present, nothing left blank.
- AccurateThe science and the data are correct and match the evidence.
- Scientific reasoningYou explain your claim with evidence and reasoning (CER), not just an answer.
- Professional communicationClear, organized, labeled, and written the way a clinician or scientist would.
- SubmittedTurned in the right way (Schoology for routine work) and confirmed.
Drop your Wed, Sep 9, 2026 · E-value and query coverage here. Use a clear file name (your initials + project). Routine work still goes to Schoology (via the CMSD portal).
Upload a project