(True or False) Inhibitors fall into three basic types which arise from body fluids(internal), substrates, or the extraction process.
True
What is the purpose of a differential DNA extraction?
To separate sperm cells from all other cells
(True or False) A pH shift from lower to higher during silica-based DNA purification assists in the elution of DNA.
True
What extraction method creates the disruption of water molecules by introducing chaotropic salts in order to bind DNA to silica?
Solid Phase
(True or False) Spematozoa are selectively lysed prior to lysing non-sperm cells because they are easier to break open.
False; Non-sperm cells are selectively lysed prior to spermatozoa because they are easier to break open/Spermatozoa are harder to break open
What amount of DNA is contained within a human diploid cell?
6 picograms
What may be added to a bead-based purification to increase the DNA yield for low concentration samples?
Carrier RNA (cRNA)
Why is dithiothreitol added when extracting DNA from hair and sperm cells?
To reduce disulfide bonds
What are the steps during solid phase extraction and what occurs during each step?
- Lyse
- Bind
- Wash
- Elute
What are the 3 main types of inhibitors?
- Internal inhibitors
- Substrate inhibitors
- Inhibitors from the extraction process
List 3 internal inhibitors.
- Heme, immunoglobulin G, hemin, bilirubin, and bile salts (Blood)
- Bacteria (Vaginal, buccal, and fecal samples)
- Melanin (Hair and tissue)
- Calcium (bone and teeth)
- Polyamines, spermine, and spermidine (sperm)
- Urea (Urine)
List 3 substrate inhibitors.
- Textile dyes - Indigo dyes used in denim
- Fabric - Tannic acid used to tan leather and resins used in “wrinkle resistant” fabrics
- Environmental samples - Humic acid found in soil and heavy metals
- Food compounds - organic compounds, phenolic compounds, glycogen, fats, and calcium in milk
List 3 inhibitors from the extraction process.
- Salts
- Guanidine
- Proteases such as PK
- Magnetic beads
- Detergents
What are the goals of DNA extraction?
To isolate and purify DNA by removing inhibitors and nucleases and separating the DNA from other cellular components.
