Related topics: genes · dna sequences · genetic variation

A chimp-pig hybrid origin for humans?

( —These days, getting a Ph.D. is probably the last thing you want to do if you are out to revolutionize the world. If, however, what you propose is an idea, rather than a technology, it can still be a valuable ...

Rare evolutionary event detected in the lab

It took nearly a half trillion tries before researchers at The University of Texas at Austin witnessed a rare event and perhaps solved an evolutionary puzzle about how introns, non-coding sequences of DNA located within genes, ...

Genes show one big European family

From Ireland to the Balkans, Europeans are basically one big family, closely related to one another for the past thousand years, according to a new study of the DNA of people from across the continent.

Portable, rapid DNA test can detect Ebola and other pathogens

Using technical advances not yet developed when the 2014 Ebola outbreak began, UC San Francisco-led scientists completed a proof-of-principle study on a real-time blood test based on DNA sequencing that can be used to rapidly ...

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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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