DNA Sequence Analysis

Among various biological data, DNA sequence is doubtlessly a fundamental datum. By obtaining particular DNA sequence data and analyzing, biologists get to understand life science more precisely. DNA sequencing refers to methods for determining the order of the nucleotides bases adenine, guanine, cytosine and thymine in a molecule of DNA. The first DNA sequence was obtained by academic researchers, using laboratories methods based on 2-dimensional chromatography in the early 1970s.

DNA sequencing is used to determine the sequence of individual genes, full chromosomes or entire genomes of an organism. DNA sequencing has also become the most efficient way to sequence RNA or proteins.

Sequencing Techniques

• Maxam-Gilbert Sequencing
  In 1976-1977, Allan Maxam and Walter Gilbert developed a DNA sequencing method based on chemical modification of DNA and subsequent cleavage at specific bases. The technique depends on the relative chemical liability of different nucleotide bonds. The method requires radioactive labelling at one end and purification of the DNA fragment to be sequenced.
• Sanger Sequencing
  The Sanger method interrupts elongation of DNA sequences by incorporating dideoxynucleotides into the sequences. The key principle is the use of dideoxynucleotide triphosphates as DNA chain terminators. The method requires a single-stranded DNA template, a DNA primer, a DNA polymerase, radioactively or fluorescently labelled nucleotides, and modified nucleotides that terminate DNA strand elongation.

Fig.1 The basic workflow information for Sanger Sequencing.

Procedure

The analysis of data recorded from DNA sequencing helps the user transform raw data into useful information. DNA seq data analysis typically involves four steps:

• Trimming of the overlapping sequence data
• Multiple alignments of obtained DNA sequences
• Checking of consistency between chromatogram peak data and reading text
• Correction of any misreads due to software limitation

Applications

• Information obtained by DNA sequencing makes it possible to understand or alter the function of genes.
• DNA sequence analysis demonstrates regulatory regions that control gene expression and genetic "hot spots" particularly susceptible to mutation.
• Comparison of DNA sequences shows evolutionary relationships that provide a framework for definite classification of microorganisms including viruses.
• Comparison of DNA sequences facilitates identification of conserved regions, which are useful for development of specific hybridization probes to detect microorganisms including viruses in clinical samples.
• DNA sequencing has become sufficiently fast and inexpensive to allow laboratory determination of microbial sequences for identification of microbes. Sequencing of the 16S ribosomal subunit can be used to identify specific bacteria. Sequencing of viruses can be used to identify the virus and distinguish different strains.
• DNA sequencing shows gene structure that helps research workers to find out the structure of gene products.

Releated Products

DNA Sequencer / Genetic Analyzer

Genetic analyzers are automated systems capable of sequencing DNA or analyzing fragments for a variety of applications. In capillary electrophoresis-based systems, DNA fragments bound to probes migrate through a polymer and the fluorescence emissions are measured. An array of multiple capillaries allows for sample loading in a convenient 96-well microplate format.

Fluorometer

Fluorometers are routinely used in molecular and cell biology laboratories to detect and quantify fluorescent light signals emitted at different wavelengths. Appropriate filtering by fluorescence instrumentation allows detection of fluorescent signals of different emission wavelengths. Fluorometers with advanced detection capabilities also detect signals from fluorescent resonance energy transfer (FRET) experiments.

Pipette

Pipette is a small piece of apparatus which typically consists of a narrow tube into which fluid is drawn by suction (as for dispensing or measurement) and retained by closing the upper end. Pipettes are a common laboratory tool and come in a multitude of channels, displacements and construction materials. There are different pipettes for all kinds of uses within the lab.

Thermal Cycler

Thermal Cycler is a laboratory apparatus that amplify segments of DNA using PCR. A thermal cycler is also commonly called a DNA Amplifier, PCR Machine, or Thermocycler. The cycle normally lowers or raises the block's temperature in preprogrammed discrete steps. A thermal cycler is important for a laboratory dealing in molecular biology and gene cloning.

Vortexer

Vortexers, or vortex mixers, have very fast, small orbits (usually between 2 and 4 mm) and they are named for their ability to form a vortex in the liquid that they are mixing. are commonly used in laboratories to mix small liquid volumes for cell disruption or homogenization. Constructed of rugged, corrosion-resistant materials, the instruments will endure heavy everyday usage.

STEMart provides you with a variety of DNA sequence analysis equipment or consumables to meet your various R&D and application needs. If you have any questions or requirements for sequence analysis, please feel free to contact us.