Lecture 4 - DNA profiling Flashcards
What are Short Tandem Repeats
Short tandem repeats (STRs) occur when a short sequence of DNA is repeated many times in a row
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Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Compare 2 Types of Species/Sample
Obtain DNA of the 2 samples
PCR/Restriction enzymes used to produce fragments of DNA
Gel Electro used to analyse DNA
Gel Electro used to Separate DNA fragments
More difference in bands indicates 2 Species are different
Extracting the DNA
Breaking up the cells (manually crushing). Separates the cells and exposes them to the soap and salt
Adding soap helps to break down the cellular and nuclear membranes to release the DNA
Adding salt causes DNA to bind together
Filtering off the debris (using a filtering device)
Protein framework of the chromosomes removed (adding protease)
Adding ethanol helps the DNA precipitate
What does adding soap do to DNA
Adding soap helps to break down the cellular and nuclear membranes to release the DNA
What does adding salt do to DNA
Adding salt causes DNA to bind together
What does adding ethanol do to DNA
Adding ethanol helps the DNA precipitate
Gel Electrophoresis
Restriction enzymes create fragments of varying sizes
DNA segments are loaded into wells
Gel floats in a buffer solution between opposite electrodes
When current turned on fragments move towards positive charged cathode
Smaller fragments travel faster and further
:Gel electrophoresis
Gel Electrophoresis allows you to separate nucleotides based on size
DNA fragments are different sizes
DNA fragments are negatively charged because of the phosphate group (move towards positive because of electric field)
Shorter fragments move faster than longer fragments
Uses of Gel Electro
Criminal cases
Paternity cases
Comparing species for classification purpose
Medical diagnosis
Identifying human remains
Animals and plant breeding
Cancer
PGD
DNA fingerprinting allows us to identify an individual from a biological sample. Because of this, it is also sometimes called what?
DNA profiling
What is the abbreviation used for the process which can multiply the DNA sample before gel electrophoresis?
PCR
