1,1

The genetic code is universal, governing the synthesis of the proteins of all living species on Earth (including bacteria and viruses).

The information giving the order of the amino-acids which are to be linked to each other to constitute the proteins is materially stored "in", "through" the DNA, "by" its succession of nucleotides materializing its two strands.

There are four nucleotides named Thymine (T), Adenine (A), Cytosine (C) and Guanine (G), which form one chain (ex: ATGGAATTCTCGCT...), named the "template".

The second chain, named the coding strand, is complementary, and its synthesis "on" the template is ruled by this chemical correspondence: A->T and T->A (by means of two hydrogen-bonds); G->C and C-> (three H-bonds). The two strands so paired constitute the DNA, which is stable.

When a gene (a chunk of the DNA) is "activated" to govern the synthesis of "its" protein, a special coding strand, the "messenger RNA" (which is the real stuff governing the synthesis of the proteins) is copied on the template, and goes in the cytoplasm where the ribosomes enter in action... The mRNA carries the same information as the coding strand, but in a slightly different form (a chemical difference in the chain, and Uridin (U) replacing Thymine).

The unity of information carried by either the coding strand and the mRNA is materialized by the linear succession of groups of three nucleotides ("triplets" of nucleotides), named also "codons" (ex: ATG-GAA-TTC-TCG-...)

The four objects T, A, C, and G taken three by three with repetitions yield 64 possibles combinations which, giving the value 1 to T, 3 to A, 2 to C and 4 to G, are the terms of this sequence.

Since there is 64 codons coding for 20 amino-acids, each amino-acid is coded by one or many codons.

The correspondence term to term between codons of this sequence and amino-acids is:

Phe, Phe, Leu, Leu, Ser, Ser, Ser, Ser, Tyr, Tyr, Ter*, Ter, Cys, Cys, Ter, Trp,

Leu, Leu, Leu, Leu, Pro, Pro, Pro, Pro, His, His, Gln, Gln, Arg, Arg, Arg, Arg,

Ile, Ile, Ile, Met**, Thr, Thr, Thr, Thr, Asn, Asn, Lys, Lys, Ser, Ser, Arg, Arg,

Val, Val, Val, Val, Ala, Ala, Ala, Ala, Asp, Asp, Glu, Glu, Gly, Gly, Gly, Gly, ...where:

Phe is phenylalanine,

Leu: leucine

Ser: serine

Tyr: tyrosine

Ter*: end signal

Cys: cysteine

Trp: tryptophan

Pro: proline

His: histidine

Gln: glutamine

Arg: arginine

Ile: isoleucine

Met: methionine (and beginning signal)

Thr: threonine

Asn: asparagine

Lys: lysine

Val: valine

Ala: alanine

Asp: aspartic acid

Glu: glutamic acid

Gly: glycine

Crick, F. H. C., 1966. The genetic code-yesterday, today and tomorrow. In The Genetic Code, Proceedings of the XXXI Cold Spring Harbor Symposium on Quantitative Biology. Cold Spring Harbor, N.Y.: Cold Spring Harbor Laboratory of Quantitative Biology, pp. 3-9.

Brian Hayes, The invention of the genetic code, in The American Scientist, Vol. 86, Number 1, Jan-Feb (1998), pages 8-14.

Shaun D. Black, University of Texas Health Center at Tyler, Genetic Code.

Adjacent sequences: A104152 A104153 A104154 this_sequence A104156 A104157 A104158

Sequence in context: A084514 A084524 A133794 this_sequence A133786 A039990 A034840

base,easy,fini,full,nonn

Alexandre Wajnberg (alexandre.wajnberg(AT)ulb.ac.be), Mar 09 2005