Scientists develop tool to sequence circular DNA

A new tool invented by University of Alberta biologists to sequence circular DNA will provide scientists with richer, more accurate data that could help advance research on viruses, agriculture and perhaps even cancer.

Droplets are key to cells' dynamic activities

A cell is a complex machine whose flexible architecture enables it to take part in life's activities: relaying information, managing waste, responding to stress.

Images reveal how bacteria form communities on the human tongue

Using a recently developed fluorescent imaging technique, researchers in the United States have developed high-resolution maps of microbial communities on the human tongue. The images, presented March 24 in the journal Cell ...

Gene switch ENO identified as a tomato fruit regulator

A team of researchers from Spain, Germany and France has identified the gene switch ENO (excessive number of floral organs) as a tomato fruit regulator. In their paper published in Proceedings of the National Academy of Sciences, ...

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DNA sequence

A DNA sequence or genetic sequence is a succession of letters representing the primary structure of a real or hypothetical DNA molecule or strand, with the capacity to carry information as described by the central dogma of molecular biology.

The possible letters are A, C, G, and T, representing the four nucleotide bases of a DNA strand — adenine, cytosine, guanine, thymine — covalently linked to a phosphodiester backbone. In the typical case, the sequences are printed abutting one another without gaps, as in the sequence AAAGTCTGAC, read left to right in the 5' to 3' direction. Short sequences of nucleotides are referred to as oligonucleotides and are used in a range of laboratory applications in molecular biology. With regard to biological function, a DNA sequence may be considered sense or antisense, and either coding or noncoding. DNA sequences can also contain "junk DNA."

Sequences can be derived from the biological raw material through a process called DNA sequencing.

In some special cases, letters besides A, T, C, and G are present in a sequence. These letters represent ambiguity. Of all the molecules sampled, there is more than one kind of nucleotide at that position. The rules of the International Union of Pure and Applied Chemistry (IUPAC) are as follows:

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