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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.
STR analysis is a tool in forensic analysis that evaluates specific STR regions found on nuclear DNA.The variable (polymorphic) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another. [3]
A polymerase chain reaction is a form of enzymatic DNA synthesis in the laboratory, using cycles of repeated heating and cooling of the reaction for DNA melting and enzymatic replication of the DNA. DNA synthesis during PCR is very similar to living cells but has very specific reagents and conditions.
The purified DNA can then be used for downstream applications such as PCR, [2] sequencing, or cloning. Currently, it is a routine procedure in molecular biology or forensic analyses. This process can be done in several ways, depending on the type of the sample and the downstream application, [ 3 ] the most common methods are: mechanical ...
There are two fundamental differences between the methods. One is that molecular cloning involves replication of the DNA within a living cell, while PCR replicates DNA in the test tube, free of living cells. The other difference is that cloning involves cutting and pasting DNA sequences, while PCR amplifies by copying an existing sequence.
Polymerase cycling assembly (or PCA, also known as Assembly PCR) is a method for the assembly of large DNA oligonucleotides from shorter fragments. The process uses the same technology as PCR, but takes advantage of DNA hybridization and annealing as well as DNA polymerase to amplify a complete sequence of DNA in a precise order based on the single stranded oligonucleotides used in the process.
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. Common sources of gene duplications include ectopic recombination, retrotransposition event, aneuploidy, polyploidy, and replication slippage.
The exponential amplification via reverse transcription polymerase chain reaction provides for a highly sensitive technique in which a very low copy number of RNA molecules can be detected. RT-PCR is widely used in the diagnosis of genetic diseases and, semiquantitatively, in the determination of the abundance of specific different RNA ...