• The Basics of Specific DNA Sequencing

    Sequencing DNA is an integral part of many scientific researches and numerous applied fields, such as diagnostic, biotechnology, forensic biology, and biological systematics. In some cases, scientists need to extract and purify a specific sequence of DNA to further replicate them into thousands of other sequence. The process is also known as cloning.

    In the 1970s, academic researchers were able to obtain the first DNA sequence using two-dimensional chromatography, such as the gas chromatography and liquid chromatography. The process involves the separation of the sample into two different stages. First, the sample is injected from the first column onto the second column. While in the second column, the sample is run under a different mechanism which is faster than the first to allow a specific sequence of DNA to separate from the solution.

    Maxam-Gilbert sequencing, chain-termination methods, dye-terminator sequencing, and high-throughput sequencing are only some of the oldest sequencing techniques that are still used at present. From these methods, newer methods are born allowing the sequencing of specific DNA to be faster and easier.

    A newer available specific DNA sequencing technique is the Streptavidin-coupled Dynabeads, a solid-phase alternative to nitrocellulose that allows scientists to capture a specific sequence of RNA/DNA through magnet handling. During the process, scientists immobilize the double-stranded PCR products onto the beads. Once done, they are easily converted to single-stranded bead-bound template. Scientists use the method to capture a specific DNA molecule from the solution.

    General Idea of How Specific DNA Sequencing Works

    The process of sequencing specific DNA starts by achieving DNA replication reactions with the presence of dideoxy terminator nucleotides. Scientists heat all templates DNA, an enzyme or a variant of Taq polymerase, and a primer or a small piece of single stranded DNA. Once heated, the primer may either attach to its end location elongating the DNA or replicate into billions of copies for a single strand if there are also billions of template DNA.

    Inside the sequencing laboratory, the DNA sequencing image appears in different colors through a sequencing machine. Using the sequencing machine, scientists will apply an electrophoresis to the sample and monitor the different colors that come out. During the electrophoresis step, specific DNA fragments are piped out through a tiny glass fiber. The computer will then interpret the colors by printing the nucleotide sequence across the top of the sequencing machine.


    Categories: DNA & Genetics

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