In genetics and biochemistry, sequencing means to determine the primary structure (or primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which succinctly summarizes much of the atomic-level structure of the sequenced molecule. Genetics (from the Greek genno γεννώ= give birth) is the science of genes, heredity, and the variation of organisms. ... Biochemistry is the chemistry of life. ... A protein primary structure is a chain of amino acids. ... A biopolymer is a polymer found in nature. ...

In genetics terminology, sequencing is determining the nucleotides of a DNA or RNA strand. Currently, all sequencing is performed using the chain termination method, created by Frederick Sanger. This technique can only be used to identify fairly short sequences at a time (around 300-1000 base pairs on ABI machine), and therefore strategies to have been devised to scale the method up to sequence genes and genome. Two of the mainstream chain termination strategies are chromosome walking and shotgun sequencing. A nucleotide is an organic molecule consisting of a heterocyclic nucleobase (a purine or a pyrimidine), a pentose sugar (deoxyribose in DNA or ribose in RNA), and a phosphate or polyphosphate group. ... DNA replication Deoxyribonucleic acid (DNA) is a nucleic acid which is capable of carrying genetic instructions for the biological development of all cellular forms of life and many viruses. ... Ribonucleic acid (RNA) is a nucleic acid consisting of a string of covalently-bound nucleotides. ... The chain termination or Sanger or dideoxy method is a process used to sequence (read the bases) of DNA. It is named after Frederick Sanger who developed the process in 1975. ... This article or section should be merged with Fred Sanger Frederick Sanger OM (born August 13, 1918) is a British molecular biologist who was working on problems related to the determination of the structure of proteins. ... The chain termination or Sanger or dideoxy method is a process used to sequence (read the bases) of DNA. It is named after Frederick Sanger who developed the process in 1975. ... Chromosome walking is a method in genetics for identifying and sequencing long parts of a DNA strand, e. ... Shotgun sequencing is a method used in genetics for sequencing long DNA strands. ...

Other techniques under development, which may offer many benefits over these, include:

• Pyrosequencing
• nanopore sequencing
• GeneEngine

Methods for performing protein sequencing include: Pyrosequencing, a new method of DNA sequencing which involves the addition of phosphorylated dNTPs to the DNA polymerase reaction which emmit light upon binding to the DNA template. ... Nanopore sequencing is a currently under development method for determining the order in which nucleotides occur on a strand of DNA. A nanopore is simply a small hole, of the order of 1 nanometer in diameter. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ...

• Edman degradation
• mass spectrometry
• protease digests

Though polysaccharides are also biopolymers, it is not so common to talk of 'sequencing' a polysaccharide, because a symbolic linear depiction cannot capture their tendency to branch and to bond to one another in different ways. Edman degradation, developed by Pehr Edman, is a method of sequencing amino acids in a peptide. ... Mass spectrometry is a technique for separating ions by their mass-to-charge (m/z) ratios. ... Polysaccharides (sometimes called glycans) are relatively complex carbohydrates. ... In chemistry, a chemical bond is the force which holds together atoms in molecules or crystals. ...

See also

• Genetic code
• Sequence motif

RNA codons. ... A sequence motif is a nucleotide or amino-acid sequence pattern that is widespread and has, or is conjectured to have, a biological significance. ...

External links

• Information on genome projects, and the data they have produced (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=Genome) at the National Center for Biotechnology Information
• (2005) Genome Sequencing: Using Models to Predict Who's Next. (http://www.plosbiology.org/plosonline/?request=get-document&doi=10.1371%2Fjournal.pbio.0030025) PLoS Biol 3(1): e25.