简介：Theorganizationofthecanonicalgeneticcodeneedstobethoroughlyilluminated.Herewereorderthefournucleotides-adenine,thymine,guanineandcytosine-accordingtotheiremergenceinevolution,andapplytheorganizationalrulestodevisinganalgebraicrepresentationforthecanonicalgeneticcode.Underaframeworkofthedevisedcode,wequantifycodonandaminoacidusagesfromalargecollectionof917prokaryoticgenomesequences,andassociatetheusageswithitsintrinsicstructureandclassificationschemesaswellasaminoacidphysicochemicalproperties.Ourresultsshowthatthealgebraicrepresentationofthecodeisstructurallyequivalenttoacontent-centricorganizationofthecodeandthatcodonandaminoacidusagesunderdifferentclassificationschemeswerecorrelatedcloselywithGCcontent,implyingasetofrulesgoverningcompositiondynamicsacrossawidevarietyofprokaryoticgenomesequences.Theseresultsalsoindicatethatcodonsandaminoacidsarenotrandomlyallocatedinthecode,wherethesix-folddegeneratecodonsandtheiraminoacidshaveimportantbalancingrolesforerrorminimization.Therefore,thecontent-centriccodeisofgreatusefulnessindecipheringitshithertounknownregularitiesaswellasthedynamicsofnucleotide,codon,andaminoacidcompositions.

简介：这被相信在RNA世界上运作(ribozymes)并且参考(riboscripts)RNA分子被创造与仅仅三(腺苷，uridine，和海鸟粪正弦)并且二(腺苷和uridine)nucleosides，分别地以便遗传密码开始了不复杂。随后发展能剪贴自己和riboscripts的Ribozymes对严密编辑善于接受(到肌甙的腺苷)；RNA分子的集中的多样化塑造了能够polymerizing氨基酸的新奇细胞的机械—细胞的大楼材料的一种新类型永久。开始，遗传密码，编码七氨基酸，仅仅被创造区分嘌呤和嘧啶；它以后以编码12，15，和20的一个逐步的方法被扩展通过从它的角色的鸟嘌呤的消除的氨基酸作为运作的信号并且通过胞嘧啶的招募。因此，遗传密码的成熟也与一致与(1)从初发的翻译机械的aminoacyl-tRNA(AARS)的离开，(2)由DNA的参考RNA的代替，并且(3)AARS的合作进化和他们的血缘的tRNAs。这个模型由DNA预言做RNA的分子的机制，由蛋白质的细胞的过程，和参考利用的渐渐的代替。

简介：Thecodontableforthecanonicalgeneticcodecanberearrangedinsuchawaythatthecodeisdividedintofourquartersandtwohalvesaccordingtothevari-abilityoftheirGCandpurinecontents,respectively.Forprokaryoticgenomes,whenthegenomicGCcontentincreases,theiraminoacidcontentstendtoberestrictedtotheGC-richquarterandthepurine-contentinsensitivehalf,whereallcodonsarefourfolddegenerateandrelativelymutation-tolerant.Conversely,whenthegenomicGCcontentdecreases,mostofthecodonsretracttotheAU-richquarterandthepurine-contentsensitivehalf;mostofthecodonsnotonlyremainencodingphysicochemicallydiversifiedaminoacidsbutalsovarywhentransversion(betweenpurineandpyrimidine)happens.Aminoacidswithsixfold-degeneratecodonsaredistributedintoallfourquartersandacrossthetwohalves;theirfourfold-degeneratecodonsareallpartitionedintothepurine-insensitivehalfinfavoriteofrobustnessagainstmutations.Thefeaturesmanifestedinthere-arrangedcodontableexplainmostoftheintrinsicrelationshipbetweenproteincodingsequences(theinformationalcontent)andaminoacidcompositions(thefunctionalcontent).Therenovatedcodontableisusefulinpredictingabundantaminoacidsandpositioningtheaminoacidswithrelatedordistinctphysicochem-icalproperties.