Recombinant DNA | Result of combining DNA of two different species |
Isolation of DNA | Restriction enzymes are used in bacteria to find a recogntion site [to code sequences] along DNA and cut it at that point, using the same enzyme, gene is inserted into a plasmid |
Transfer of DNA | Plasmid vector used to transfer the DNA |
Rejoining DNA | DNA ligases used to join fragments together. Same recognition enzyme must sever the strand in the second organism so base pairs match with the fragment. |
Amplification of DNA | Transformed bacterial cells with the recombinant DNA allowed to multiply in a large scale culture → divide and replicate; rDNA replicated → amplification of the desired sequence |
Short Tandem Repeats | Short sequence of DNA - normally 2-5 base pairs repeated [no. varies person to person] |
DNA Sequencing/Profiling | Process of determining the precise order of nucleotides within a sample of DNA, involves testing of highly variable regions of DNA containing STR → located in introns |
Polymerase Chain Reaction | Technique used to exponentially amplify the number of copies of a specific DNA sequence [DNA samples typically found in trace amounts → must be amplified] |
Gel Electrophoresis | Mixturees of DNA separated based on molecular size. DNA molecules (negatively charged) pushed by an electric field through the gel towards the positive terminal. [Used in DNA profiling to compare to a known standard] |
Steps of PCR | 1. Denaturation: DNA sample is heated to high temperature (94-98°C), causing the double-stranded DNA to separate into single strands.
2. Annealing: Temperature is lowered (typically 50-65°C), allowing short DNA primers to bind to specific target sequences on each single strand.
3. Extension: Temperature is raised (72°C), and DNA polymerase synthesizes complementary strands by adding nucleotides to the primers, creating new DNA segments.
4. Repeat: The cycle is repeated multiple times (20-40 cycles), exponentially amplifying the target DNA region. |