CGL Laboratory Safety and Procedures 3 — Questions and Answers
Question 1: When conducting a DNA extraction in a genealogical lab, why must the work area be cleaned with a 10% bleach solution before and after each session?
- To satisfy EPA disposal regulations
- To deactivate exogenous DNA that could contaminate samples (Correct answer)
- To sterilize equipment for reuse
- To comply with ADA lab accessibility standards
Correct answer: To deactivate exogenous DNA that could contaminate samples
A 10% bleach solution degrades extraneous DNA on surfaces, preventing cross-contamination between samples.
Question 2: What is the purpose of a negative control sample in a genealogical DNA analysis workflow?
- To represent the expected result for a confirmed match
- To verify that reagents and the environment are free of contamination (Correct answer)
- To calibrate the PCR machine's thermal cycle
- To provide a reference for paternal haplogroup assignment
Correct answer: To verify that reagents and the environment are free of contamination
A negative control contains no DNA; any signal it produces indicates contamination in the reagents or environment.
Question 3: An archivist discovers that a microfilm roll has become brittle and begins to crack during handling. What is the safest immediate action?
- Humidify the roll in a sealed bag with a damp sponge overnight
- Attempt to unspool and digitize it as quickly as possible
- Discard the roll and note the loss in the finding aid
- Transfer it to a conservation specialist without further handling (Correct answer)
Correct answer: Transfer it to a conservation specialist without further handling
Brittle microfilm requires professional conservation treatment; continued handling risks destroying irreplaceable images.
Question 4: Which type of fire extinguisher is appropriate for an archive lab that contains paper records, electrical equipment, and chemical solvents?
- Class A only
- Class B only
- Class ABC multi-purpose extinguisher (Correct answer)
- Class D extinguisher
Correct answer: Class ABC multi-purpose extinguisher
A Class ABC extinguisher covers ordinary combustibles (paper), flammable liquids (solvents), and electrical fires — all hazards present in an archive lab.
Question 5: What is the recommended relative humidity (RH) range for storing original genealogical documents to prevent both mold growth and brittleness?
- 10–20% RH
- 30–50% RH (Correct answer)
- 60–70% RH
- 75–85% RH
Correct answer: 30–50% RH
A range of 30–50% RH inhibits mold while keeping paper flexible enough to avoid cracking from excessive dryness.
Question 6: A genealogical researcher needs to transport a DNA buccal swab sample by mail. Which federal agency's regulations govern this shipment?
- USPS Domestic Mail Manual only
- DOT/IATA hazardous materials regulations for biological substances (Correct answer)
- FDA regulations for in-vitro diagnostic devices
- EPA regulations for biological waste transport
Correct answer: DOT/IATA hazardous materials regulations for biological substances
Biological specimens shipped by air or ground must comply with DOT/IATA Category B (UN 3373) packaging and labeling requirements.
Question 7: In a genealogical digitization workflow, what does 'color calibration' of a scanner primarily ensure?
- That scan files are compressed to the smallest possible size
- That the digital image accurately reproduces the original document's colors and tones (Correct answer)
- That all scans are converted to grayscale for uniformity
- That metadata is embedded automatically in each file
Correct answer: That the digital image accurately reproduces the original document's colors and tones
Color calibration using a target chart ensures the scanner reproduces true colors, which is critical for accurately preserving ink tones and paper condition in the digital surrogate.
CGL Laboratory Safety and Procedures 3
When conducting a DNA extraction in a genealogical lab, why must the work area be cleaned with a 10% bleach solution before and after each session?