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A strip of eight PCR tubes, each containing a 100 μL reaction mixture Placing a strip of eight PCR tubes into a thermal cycler. The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study.
Because unrelated people almost certainly have different numbers of repeat units, STRs can be used to discriminate between unrelated individuals. These STR loci (locations on a chromosome) are targeted with sequence-specific primers and amplified using PCR. The DNA fragments that result are then separated and detected using electrophoresis.
Multiplex-PCR consists of multiple primer sets within a single PCR mixture to produce amplicons of varying sizes that are specific to different DNA sequences. By targeting multiple sequences at once, additional information may be gained from a single test run that otherwise would require several times the reagents and more time to perform.
DNA replication is a natural form of copying DNA with the amount of genes remaining constant. However, the amount of DNA or the number of genes can also increase within an organism through gene duplication, a major mechanism through which new genetic material is generated during molecular evolution.
[73] [72] DNA of up to 35,000 basepairs was synthesized by Wayne M. Barnes by using different mixtures of A and B type polymerases, [36] [72] thereby creating the long-range PCR. The high synthesis rate of KOD polymerase was published in 1997 by Masahiro Takagi and colleagues, [ 3 ] [ 72 ] [ 14 ] thereby creating the fundamentals of high speed PCR.
An extension of the 'colony-PCR' method (above), is the use of vector primers. Target DNA fragments (or cDNA) are first inserted into a cloning vector, and a single set of primers are designed for the areas of the vector flanking the insertion site. Amplification occurs for whatever DNA has been inserted. [4] PCR can easily be modified to ...
DNA replication also works by using a DNA template, the DNA double helix unwinds during replication, exposing unpaired bases for new nucleotides to hydrogen bond to. Gene synthesis, however, does not require a DNA template and genes are assembled de novo. DNA synthesis occurs in all eukaryotes and prokaryotes, as well as some viruses. The ...
Reverse transcription polymerase chain reaction (RT-PCR) is a laboratory technique combining reverse transcription of RNA into DNA (in this context called complementary DNA or cDNA) and amplification of specific DNA targets using polymerase chain reaction (PCR). [1] It is primarily used to measure the amount of a specific RNA.