DNA sequencer

DNA sequencer
DNA sequencers

A DNA sequencer is a scientific instrument used to automate the DNA sequencing process. It can be also considered an optical instrument as it generally analyses light signals originating from fluorochromes attached to nucleotides.

DNA sequencers have become more important due to large genomics projects and the need to increase productivity.

Modern automated DNA sequencing instruments (called DNA sequencers) are able to sequence multiple samples in a batch (run) and perform as many as 24 runs a day. These perform only the size separation and peak reading; the actual sequencing reaction(s), cleanup and resuspension in a suitable buffer must be performed separately.

The magnitude of the fluorescent signal is related to the number of strands of DNA that are in the reaction. If the initial amount of DNA is small, the signals will be weak. However, the properties of PCR allow one to increase the signal by increasing the number of cycles in the PCR program.

A simple DNA sequencer will have one or more lasers that emit at a wavelength that is absorbed by the fluorescent dye that has been attached to the DNA strand of interest. It will then have one or more optical detectors that can detect at the wavelength that the dye fluoresces at. The presence or absence of a strand of DNA is then detected by monitoring the output of the detector. Since shorter strands of DNA move through the gel matrix faster they are detected sooner and there is then a direct correlation between length of DNA strand and time at the detector. This relationship is then used to determine the actual DNA sequence.

The output of these machines is not perfect as it may contain reading errors and needs to be processed (see Sequence assembly). Until a few years ago, this task was done manually by an operator. The assembly process for a contig made of 10 samples took about 5–15 minutes, depending on the quality of the samples. However, today, modern software can automatically process the output in seconds.

See also


Wikimedia Foundation. 2010.

Игры ⚽ Нужно решить контрольную?

Look at other dictionaries:

  • Sequencer — A sequencer is something that either generates or analyzes a sequence, or triggers events in timed fashion. The term may mean or refer to:* Sequencer , a 1976 electronic music album by Larry Fast * Sequencer (album), a 1996 musical album by… …   Wikipedia

  • Sequencer — bezeichnet ein Gerät oder eine Software zur Erstellung von Musik, siehe Sequenzer (Musik) in der Rechnerarchitektur das Mikroprogrammsteuerwerk die Spielhilfe einer Orgel, siehe Kombination (Orgel) in der Molekularbiologie ein DNA… …   Deutsch Wikipedia

  • DNA sequencing — Part of a series on Genetics Key components Chromosome DNA • RNA Genome Heredity Mutation Nucleotide Variation …   Wikipedia

  • Music sequencer — Contents 1 Modern sequencers 2 Software sequencers / DAWs with sequencing features 2.1 …   Wikipedia

  • Protein sequencer — A protein sequencer is a machine that is used to determine the sequence of amino acids in a protein.They work by tagging and removing one amino acid at a time , which is analysed and identified. This is done repetitively for the whole polypeptide …   Wikipedia

  • 454 Life Sciences — 454 Life Sciences, a Roche company, is a biotechnology company based in Branford, Connecticut specializing in high throughput DNA sequencing using a novel massively parallel sequencing by synthesis approach. 454 has experienced rapid growth since …   Wikipedia

  • Applied Biosystems — Applied Biosystems, Inc. (formerly nasdaq2|ABIO) is the original name of a pioneer biotechnology company founded in 1981 in Foster City, California, in the San Francisco Bay Area. [http://marketing.appliedbiosystems.com/mk/get/25YRSEMS HERRITAGE… …   Wikipedia

  • Leroy Hood — is an American biologist. He won the 2003 Lemelson MIT Prize for inventing four instruments that have unlocked much of the mystery of human biology by helping decode the genome. [ [http://web.mit.edu/invent/a winners/a hood.html 2003 Lemelson MIT …   Wikipedia

  • Terminal restriction fragment length polymorphism — (TRFLP or sometimes T RFLP) is a molecular biology technique for profiling of microbial communities based on the position of a restriction site closest to a labeled end of an amplified gene. The method is based on digesting a mixture of PCR… …   Wikipedia

  • Hood , Leroy Edward — (1938–) American biologist Born in Missoula, Montana, Hood was educated at the California Institute of Technology, where he obtained his PhD in biochemistry in 1964, and at Johns Hopkins Medical School, Baltimore, where he qualified as an MD in… …   Scientists

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”