Dna Profiling

Front 1

Short tandem repeats (STR)

Back 1

Repeating sequences of 2-4 nucleotide bases mainly located mainly in the introns.

Front 2

Restriction enzymes

Back 2

Make cuts in the DNA at specific sites

Front 3

Restriction endonucleases

Back 3

Restriction enzyme that cut DNA in pieces

Front 4

Gel electrophoresis

Back 4

1. Restriction enzymes cleave DNA into smaller segments of various sizes

2. DNA segments are loaded into wells in a porous agarose gel. Gel floats in the buffer solution in the chamber between two electrodes

3. When electric current is passed through the gel. DNA fragments move to the positively charged anode.

4. Smaller segments move faster and further than larger ones.

5. DNA fragments can be visualised be adding a fluorescent dye - ethidium bromide into gel

6. It binds to DNA and fluoresces when placed under ultraviolet light.

7. DNA fragments show up as bands pattern and position of which are unique for every individual.

Front 5

Southern blotting

Back 5

1. After using electrophoresis alkiline solution is pulled upwards through the gel to a sheet of nitrocellulose laid on the top of it, transferring the DNA to the paper

2. The paper is exposed to a solution containing radioactively labled probe

3. A photographic film laid on top of the paper is exposed by the radioactivity in the bond probe to form an image corresponding to DNA bands

Front 6

Polymerase chain reaction (PCR)

Back 6

1. DNA polymerase, primers and free nucleotides are needed

2. There are three temperature steps repeated 30 times

3. Step I 94°C 30 sec – denaturation of DNA

4. Step II 55°C 20 sec – primer annealing

5. Step III 72° 1 min – DNA elognation be the polymerase