What separated DNA fragments look like under ultraviolet light – a smear.
Picture is orientated like the picture above – the holes are by the labels.
You can get DNA from any cell/tissue such as muscle, semen, saliva but blood is normally easiest.
The blood is treated with a series of chemicals until pure DNA emerges as a white solid.
This “restriction enzyme” doesn’t cut randomly in the DNA, but at specific letter sequences.
This stage involves adding the restriction enzyme (colourless liquid) to the DNA (another colourless liquid), using a pipette. Extraction of DNA All cells (except red blood cells) in all living creatures contain DNA.DNA can be thought of as a length of letters A, C, G and T (6 billion of them in a human cell).Technical improvements, including a number of additional DNA probes and various DNA fragment detection methods, have since been published.With the recent advent of the PCR technique (Polymerase Chain Reaction) and PCR-based methods like RAPD (Random Amplified Polymorphic DNA), DNA fingerprinting has widened its applicability and attracted a growing number of scientists.The gel is placed in a colourless liquid and electrodes are attached to the gel equipment, and a power supply is turned on.By putting the liquid DNA fragments in the hole at one end and passing an electric current through the gel, the DNA fragments move into the gel with the electric current.At this stage, the DNA can be seen as a smear in the gel rather than the “lots of bands” that is characteristic of DNA fingerprints – that is what comes later.A gel (similar to one Alec would have used, for DNA fingerprinting, they are larger but essentially the same).Some letters code for proteins, which then do stuff in the cell (like making the cell move or speeding up chemical reactions).Other letters do nothing at all and are just “spacer” or “junk” DNA.