Lab 4 Flashcards
How identical are human genomes, on average?
99.9%
What are the variable regions in genomes called?
Polymorphic
What are transposable elements?
Short DNA sequences (100-1000bps) that can move to other parts of the genome.
What is the Alu element?
A 300 bp transposable element.
Do Alu insertions usually harm a human genome?
Typically they occur in non-functional areas of DNA, such as introns and thus do not have harmful effects. Can have effects if inserted into important genes.
What characterizes the tPA25 Alu insertion?
Dimorphic, phenotypically neutral as it occurs in an intron.
What are the possible ways an individual can be affected by the tPA25 Alu insertion and their corresponding PCR results?
- Homozygous for insertions, PCR produces 400 bp product
- Homozygous for no insertions, PCR produces 100 bp product
- Heterozygous; PCR produces 400 bp and 100 bp products
How are positive ions removed from the lysate?
To remove these positive ions, cell lysate is mixed with Chelex (BIO-RAD, #1421253), a grainy resin with a negatively charged surface which binds to metal ions under alkaline conditions.
How will we limit DNA degredation in this lab in the short and long term?
To limit these activities, cheek cell lysates should be stored on ice until it is used for PCR. For long term storage, lysates can be frozen at -20°C which will keep DNA intact for weeks.
What is a pellet?
Materials collected at the bottom of tube after centrifugation.
What is a supernatant?
Solution remaining after centrifugation, above the pellet.
What does it mean to resuspend a pellet?
Re-dissolve the pellet in a new solution
Is your DNA in the pellet or supernatant?
Supernatant
What is PCR?
Polymerase Chain Reaction (PCR) is a powerful method used to selectively amplify a specific region of a DNA template.
What are the three steps of PCR?
Denaturation, annealing, elongation
