Introduction to Genetics Technology
There are many different technologies associated with genetics as a science. These include genetic fingerprinting, PCR amplification, electrophoresis, and many others. This page is an introduction to and overview of these technologies.
PCR (polymerase chain reaction) amplification is an extremely powerful technique by which a single molecule of DNA can be amplified millions of times in a single afternoon. The technique has enormous applications fields from forensic science, where it can amplify trace DNA samples left at the scene of a crime; to archaeology, where it can show some of the genome of ancient organisms; to modern hospital testing, where the DNA in a tiny blood sample can be used for literally hundreds of genetic tests.
PCR amplification was invented by Kary Mullis in 1983, though something like it was suggested but never tested by Gobind Khorana several years earlier. The technique is incredibly easy to use and adapt. To use PCR, a scientist simply has to take a DNA sample and place it in a solution with the primers (oligonucleotides)that border a part of the sequence the scientist is looking for. Nucleotide bases and copying enzyme are then added to the mix. When this solution is regularly heated and cooled, the "target" DNA sequence is amplified millions of times.
Electrophoresis is a method of separating DNA fragments of different lengths. The DNA samples are placed in tiny "wells" at one end of an agarose gel. An electric current is then passed over the gel, separating the fragments. The DNA bands are then revealed with a radioactive probe.
Genetic fingerprinting is a powerful forensic tool used to identify the perpetrator of a crime through traces of genetic material left at the scene. It utilizes repetitions of DNA sequences, which differ from person to person, to uniquely identify an individual. A multi-locus probe searches for multiple repetitions of several different DNA sequences. It is highly individualized, and is one of the best ways to get an unequivocal identification of a person. A single-locus probe searches for repetitions of only one specific sequence. It works with 50 times less genetic material, but is less definitive in its results. Scientists often use three or four single-locus probes to identify individuals, whereas only one multi-locus probe would work.
Genes from one organism can be spliced into another using a technique called gene splicing. If a scientist wanted to splice human genes into a bacterial plasmid, he would first cut both DNA fragments with the same restriction enzyme (an enzyme that breaks DNA at certain base sequences, leaving "sticky ends"). He would then take the human gene he wanted to splice into the plasmid and connect them using the "sticky ends" left by the enzymes. He would probably then add strengthening enzymes to strengthen the bond between the DNA fragments. The transgenic bacterium would most likely then be allowed to divide repeatedly, and the resulting bacterial colony would then express the gene.
Even as these words are read, new technologies in genetics are being developed and tested. Enormous number of discoveries are waiting to happen, and innovations are waiting to be made. Using these and other technologies, humanity will advance into the 21st century knowledgeable about its past, present, and future.
Created by Kate Stafford and Michael Mannor for ThinkQuest.
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