Exam 3 Flashcards
(46 cards)
Forward Genetic Screen
Used to identify animals with abnormal phenotypes
Typically done in flies or worms
Reverse genetic screens
Takes a known gene and breaks it to observe the outcome
Microarray
Used to measure and compare gene expression from biological samples
Extracts RNA from the sample and used an enzyme (reverse transcriptase) to make cDNA
What is cloning?
Technique that’s used to make copies of a specific DNA fragment
How does cloning work?
It needs the DNA fragment to be isolated using restriction digests or PCR.
Then the gene is inserted into a plasmid and the fragment is inserted into the host cell (bacteria most common)
What is a DNA vector?
It is a carrying vehicle that holds an isolated DNA sequence of interest.
Features: can replicate autonomously in host cell and can take on sequences of DNA
What are common DNA vectors?
Plasmids or Phages
What is a Plasmid?
It is a circle of DNA that contains specific restriction sites, which allow for cutting then insertion. It also indicates if the gene has been inserted.
The restriction site is usually in the middle of a marker
Three main features of vectors?
1) An origin of replication
2) Restriction Site
3) Selectable marker
Restriction Enzymes
What is Gel Electrophoresis?
It is used to isolate, identify, and characterize properties of DNA.
What is PCR?
PCR targets and selectively amplifies specific sequences in genomes.
Temperature and polymerase is used to cycle through copy, separate, anneal, and then copy
What are Primers used for in PCR?
They are used to target the specific sequence
Steps to PCR?
1) Denaturation
2) Annealing
3) Extension: new nucleotides are added to the 3’ end of the extending strand
DNA sequencing
What is Southern Blot?
It is used to identify presence of known DNA sequence in samples
What is Northern Blot?
It’s used to identify presence of RNA in samples
What is Gene Delivery?
It is introducing a gene into an organism to observe its function or take advantage of its function
Gene Delivery Strategies
- Physical gene delivery
- Chemical gene delivery: uses chemicals to porate cells and deliver DNA
- Viral gene delivery
Physical gene delivery techniques
- Microinjection: injecting DNA into the cell with a miniscule probe
- Electroporation: using an applied electrical field
- In utero elecroporation: controls gene expression at specific points in development
- Gene Gun: Gun is aimed at specimen, Gas breaks the rupture disk which drives the bullet down the shaft, Bullet is blocked by the filter screen and DNA-coated metal particles emerge
Chemical Gene Delivery
- Calcium Phosphate transfection: Solution with DNA and calcium chloride, HEPES buffered saline solution causes DNA to precipitate out of solution, the solution with precipitate is added to cells
- Lipofection: lipids formed into liposome around DNA and then caused to fuse with the cell and introduce DNA
Viral gene Delivery
- starts with transfecting cells with plasmid encoding viral particles and the gene of interest, after two days, the viral-containing supernatant is collected and a centrifuge is used to collect the viral pellet. then the pellet is resuspended in buffer.
- Cultured cell line: used to produce copies of plasmid and viral particles
What is LacZ and its technique?
LacZ is a restriction site.
What are reporter genes?
They indicate the location of a protein, cell type, or circuit