Presentation on theme: "What do these terms mean to you? You have 5 min to discuss possible meanings and examples with your group! DNA sequencing DNA profiling/fingerprinting."— Presentation transcript:
What do these terms mean to you? You have 5 min to discuss possible meanings and examples with your group! DNA sequencing DNA profiling/fingerprinting Gene cloning Transformation Making artificial genes
DNA Amplification A crime scene (body tissue samples) Fragments of DNA from a long extinct animal A single viral particle (from an infection) Using the technique called polymerase chain reaction (PCR), researchers are able to create vast quantities of DNA identical to trace samples. This process is also known as DNA amplification. Many procedures in DNA technology require substantial amounts of DNA to work with, for example; DNA sequencing DNA profiling/fingerprinting Gene cloning Transformation Making artificial genes Samples from some sources, including those shown here, may be difficult to obtain in any quantity.
PCR Equipment Amplification of DNA can be carried out with simple-to-use PCR machines called thermal cyclers (shown below). Thermal cyclers are in common use in the biology departments of universities as well as other kinds of research and analytical laboratories.
The Process of PCR 1 Primer annealed A DNA sample called the target DNA is obtained DNA is denatured (DNA strands are separated) by heating the sample for 5 minutes at 98 C The temperature is lowered to 50 C Primers (short strands of mRNA) are annealed (bonded) to the DNA
The Process of PCR 2 Nucleotides After one cycle, there are now two copies of the original sample. The sample is heated to 60 ° C. A thermally stable Taq polymerase enzyme binds to the primers on each side of the exposed DNA strand. This enzyme synthesizes a complementary strand of DNA using free nucleotides.
Although only three cycles of replication are shown here, following cycles replicate DNA at an exponential rate and can make literally billions of copies in only a few hours. Polymerase Chain Reaction PCR cycles No. of target DNA strands 12 24 38 416 532 664 7128 8256 9512 101024 112048 124096 138192 1416 384 1532 768 1665 536 17131 072 18262 144 19524 288 201 048 576 212 097 152 224 194 304 238 388 608 2416 777 216 2533 554 432 Cycle 1 Cycle 2 Cycle 3 Original DNASample
Can you match the definitions below to the key words on your worksheet? This enzyme can add complementary nucleotides to a DNA strand during DNA synthesis. It is similar to the human DNA polymerase responsible for copying your genome every time one of your body cells divides. These are short pieces of single-stranded DNA that match up to DNA sequences either side of the region of genomic DNA that you would like to copy. One is a forward primer and one is a reverse primer. When they have bound to the complementary sequences on the genomic DNA template strand, they show the Taq polymerase where to start DNA synthesis. The primers are responsible for making sure that only the region of interest is copied. This is double-stranded genomic DNA isolated from the cells of the organism being studied. It can be human DNA, plant DNA, mouse DNA, bacterial DNA, whatever DNA you would like to have copied! Free floating single nucleotides must be present in the reaction because they are what the Taq puts in place during DNA synthesis.