Genetics

Researchers find genetic link to tuberculosis

About one in five people are infected with Mycobacterium tuberculosis, the microbe that causes tuberculosis. Most, however, will never develop symptoms; and for decades researchers have been stumped as to why some people ...

Cancer

Gene defends against onset of acute leukaemia

Institute scientists have revealed that a gene called PHF6 plays a powerful role in protecting against blood cancer. The study showed how a breakdown in the gene's function could accelerate the development of T cell acute ...

Genetics

Genetic defects without consequences

Many diseases are caused by genetic defects. However, their severity can vary among individual patients, so that even mild forms can occur. Scientists at the Max Planck Institute for Heart and Lung Research in Bad Nauheim ...

Genetics

Researchers identify 'beauty spots' in the genome

Genes play a role in determining the beauty of a person's face, but that role varies with the person's sex, according to a new study by Qiongshi Lu and colleagues at the University of Wisconsin-Madison, published 4th April ...

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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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