DNA technology Flashcards
What is PCR?
Polymerase Chain Reaction
How does it work?
- Heat DNA section to 95C
- Cool to 40-60C; this is to allow the anneal primers to be attached. The primers exist to stop two DNA strands from rejoining and to bracket the section being copied.
- Free nucleotides and DNA polymerase are added.
- The mixture is heated to 70C. Polymerase copies each strand starting at the primers.
- The polymerase must be thermostable. The polymerase is called taq polymerase and is from hot springs.
- The two strands formed following the PCR process can be used to repeat the process upon.
What are genetic markers?
DNA sequence with a known location on a chromosome that can be used to identify organisms
Describe some of the genetic markers
Microsatellite Repeated Sequences (MRSs)- Non coding DNA with many repeated sequences.
Single Nucleotide Polymorphisms (SNPs)- a single variated nucleotide.
Restriction Endonuclease Enzymes (REE)-Enzymes that cut DNA at specific nucleotide sequences. When equivalent sequences are cut with the same restriction enzyme they are called RFLPs (Restriction Fragment Length Polymorphisms) .
What are genetic probes?
Genetic probes are known DNA sequences that are radioactively or fluorescently labelled.
How do they work?
Seperate strands of DNA. The probe will form base pairs with the strand. The DNA is marked, and will be detected by x-ray(radioactive) or UV (fluorescent).
Gel electrophoresis
Separates DNA according to length.
Shorter fragments go further as they move more easily through the gel
The electric current causes them to travel.
How does genetic fingerprinting work?
-DNA is extracted from the sample
-REEs cut the DNA into different sized fragments
Gel electrophoresis separates the fragments on the basis of size
-DNA is treated to make it single stranded
-Probes are added
-Labelled DNA is added to an x-ray film and appears as a pattern off bars (DNA fingerprint)
