460:. Failure to obtain 18S sequences of single taxa is considered a common phenomenon but is rarely ever reported. Secondly, in contrast to initially high hopes, 18S cannot resolve nodes at all taxonomic levels and its efficacy varies considerably among clades. This has been discussed as an effect of rapid ancient radiation within short periods. Multigene analyses are currently thought to give more reliable results for tracing deep branching events in Metazoa but 18S still is extensively used in phylogenetic analyses.
173:
25:
443:
During the latter part of the 2000s, and with increased numbers of taxa included into molecular phylogenies, however, two problems became apparent. First, there are prevailing sequencing impediments in representatives of certain taxa, such as the mollusk classes
416:
is a key cause for its omnipresence in eukaryotic life. Meanwhile, the gene maintains a high degree of conservation under a persistent selective pressure in all living beings, highlighting its potential for comparison between distantly related clades.
405:
Multiple properties of the genomic sequence of the 18S rRNS have established it as an important marker gene for large-scale phylogenetic analysis and the reconstruction of the
501:"Fast evolving 18S rRNA sequences from Solenogastres (Mollusca) resist standard PCR amplification and give new insights into mollusk substitution rate heterogeneity"
692:"The structure of the yeast ribosomal RNA genes. I. The complete nucleotide sequence of the 18S ribosomal RNA gene from Saccharomyces cerevisiae"
882:
605:
Field KG, Olsen GJ, Lane DJ, Giovannoni SJ, Ghiselin MT, Raff EC, Pace NR, Raff RA (1988). "Molecular phylogeny of the animal kingdom".
75:
586:
374:
screening, allowing the amplification of unspecified or random targets from environmental samples as well as uncharacterized
827:
Tautz D, Hancock JM, Webb DA, Tautz C, Dover GA (1988). "Complete sequences of the rRNA genes of
Drosophila melanogaster".
314:
The length of the 18S rRNA varies considerably in the eukaryotic phylogenetic tree, corresponding to a range of 16S-19S in
875:
829:
655:
137:
Given its ubiquitous presence in eukaryotic life, the evolution of the 18S rRNA was soon proposed as marker for
806:
217:
213:
193:
185:
181:
868:
343:
225:
393:
In the case of 18S rRNA, retrieval of DNA is improved by the abundance of repeating sequences of the
351:
102:. Similar to the prokaryotic 16S rRNA, the genes of the 18S ribosomal RNA haven been widely used for
266:
386:
covering the less strictly conserved segments then allows the assignment of a sample to biologic
302:
130:
which were first characterized by their sedimentation properties and named according to measured
1216:
1132:
1088:
696:
409:
39:
1178:
1160:
1155:
1107:
950:
932:
653:
Hillis DM, Dixon MT (1991). "Ribosomal DNA: Molecular
Evolution and Phylogenetic Inference".
1150:
927:
756:
616:
512:
342:
and generally high degree of conservation in evolution allow the construction of universal
842:
8:
1027:
573:] (in German) (6th ed.). Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg.
375:
229:
760:
620:
516:
370:
Primers binding in highly conserved regions of the 18S rRNA are an important marker for
38:
Please expand the article to include this information. Further details may exist on the
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233:
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Rubtsov PM, Musakhanov MM, Zakharyev VM, Krayev AS, Skryabin KG, Bayev AA (1980).
798:
387:
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Early studies utilizing the 18S rRNA sequence constructed the first large-scale
437:
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are present with several hundred copies in the active genome, clustered in
87:
850:
776:
727:
676:
636:
428:. Evidence from further studies led to the creation of several important
359:
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99:
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The genomic sequence of the 18S rRNA is organized in a group with the
1018:
768:
457:
449:
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237:
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within eukaryotic cells, promoting the sensitivity of the analysis.
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24:
354:. The possible applications mirror molecular methods involving
468:
This article incorporates CC-By-2.0 text from the reference.
429:
323:
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Homo sapiens RNA, 18S ribosomal N5 (RNA18SN5), ribosomal RNA
1070:
1042:
1000:
977:
604:
318:, with the average length commonly given as around 2000
126:
was early identified as integral structural element of
498:
890:
826:
412:. The integral role in formation and function of the
788:
786:
741:Salim M, Maden EH (1981). "Nucleotide sequence of
560:
558:
556:
554:
783:
1208:
745:18S ribosomal RNA inferred from gene sequence".
551:
248:18S rRNA nucleotide length of selected species
176:General organization of the eukaryotic nuclear
499:Meyer A, Todt C, Mikkelsen NT, Lieb B (2010).
232:, these genes are transcribed together by the
876:
648:
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652:
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106:and biodiversity screening of eukaryotes.
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643:
534:
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473:
456:taxa, and the enigmatic crustacean class
365:
148:
820:
734:
595:
171:
76:Eukaryotic small ribosomal subunit (40S)
1209:
864:
843:10.1093/oxfordjournals.molbev.a040500
564:
18:
16:Part of the eukaryotic ribosomal RNA
159:structural RNA of the small subunit
109:
13:
326:has a length of 1869 nucleotides.
226:nucleolus organizer regions (NORs)
14:
1228:
220:spacer regions. These regions of
400:
23:
830:Molecular Biology and Evolution
656:The Quarterly Review of Biology
212:, separated and flanked by the
334:The universal presence of the
1:
463:
180:tandem repeats consisting of
807:National Library of Medicine
141:to resolve the evolution of
36:about Rfam SSU_rRNA_eukarya.
7:
74:. It is a component of the
10:
1233:
1192:
1131:
1087:
1026:
1017:
960:
903:
579:10.1007/978-3-662-44817-5
352:polymerase chain reaction
236:and are processed in the
505:BMC Evolutionary Biology
267:Saccharomyces cerevisiae
629:10.1126/science.3277277
526:10.1186/1471-2148-10-70
329:
303:Drosophila melanogaster
697:Nucleic Acids Research
366:Biodiversity screening
201:
149:Structure and function
82:homologue of both the
34:is missing information
710:10.1093/nar/8.23.5779
565:Graw, Jochen (2015).
378:from collections for
175:
222:ribosomal DNA (rDNA)
139:phylogenetic studies
104:phylogenetic studies
1199:(See article table)
761:1981Natur.291..205S
621:1988Sci...239..748F
517:2010BMCEE..10...70M
249:
230:ribosome biogenesis
122:in eukaryotes, the
66:) is a part of the
1194:Ribosomal proteins
803:18S ribosomal RNA"
422:phylogenetic trees
384:sequence alignment
322:. The 18S rRNA of
247:
202:
1204:
1203:
1188:
1187:
755:(5812): 205–208.
704:(23): 5779–5794.
615:(4841): 748–753.
588:978-3-662-44816-8
348:DNA amplification
312:
311:
240:structure of the
155:18S ribosomal RNA
60:18S ribosomal RNA
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56:
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234:RNA polymerase I
110:Research history
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809:. 25 March 2023
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114:Along with the
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837:(4): 366–376.
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743:Xenopus laevis
733:
682:
669:10.1086/417338
642:
594:
587:
550:
471:
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438:Lophotrochozoa
432:, such as the
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380:DNA sequencing
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316:Svedberg units
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279:Xenopus laevis
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132:Svedberg units
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3:
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663:(4): 411–53.
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446:Solenogastres
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401:Phylogenetics
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68:ribosomal RNA
65:
62:(abbreviated
61:
51:
48:December 2020
41:
35:
32:This article
30:
26:
21:
20:
1122:MT-RNR1, 12S
1103:MT-RNR2, 16S
1077:
834:
828:
822:
811:. Retrieved
801:Homo sapiens
800:
793:
752:
746:
742:
736:
701:
695:
685:
660:
654:
612:
606:
570:
566:
511:(1) 70: 70.
508:
504:
467:
442:
419:
410:tree of life
404:
392:
372:biodiversity
369:
335:
333:
313:
301:
291:Homo sapiens
289:
277:
265:
258:
253:
214:ITS-1, ITS-2
203:
184:, 18S rRNA,
165:cytoplasmic
154:
152:
136:
123:
113:
88:mitochondria
63:
59:
58:
45:
33:
1133:Chloroplast
1028:Cytoplasmic
452:, selected
360:prokaryotes
320:nucleotides
100:prokaryotes
1019:Eukaryotes
813:2024-06-29
464:References
340:eukaryotes
163:eukaryotic
143:eukaryotes
72:eukaryotes
458:Remipedia
450:Tryblidia
434:Ecdysozoa
376:specimens
238:nucleolus
210:5.8S rRNA
190:5.8S rRNA
128:ribosomes
120:5.8S rRNA
80:cytosolic
40:talk page
1211:Category
962:Bacteria
898:subunits
896:ribosome
571:Genetics
545:20214780
414:ribosome
407:metazoan
356:16S rRNA
336:18S rRNA
198:28S rRNA
167:ribosome
124:18S rRNA
96:plastids
92:16S rRNA
90:and the
84:12S rRNA
78:and the
64:18S rRNA
1117:(39S):
1108:MT-tRNA
1098:(28S):
905:Archaea
851:3136294
777:7015146
757:Bibcode
728:7008030
677:1784710
637:3277277
617:Bibcode
608:Science
567:Genetik
536:2841657
513:Bibcode
454:bivalve
426:metazoa
424:of the
344:primers
254:Species
242:nucleus
161:in the
157:is the
849:
775:
748:Nature
726:
719:324341
716:
675:
635:
585:
543:
533:
430:clades
388:clades
324:humans
308:1,995
296:1,869
284:1,825
272:1,789
228:. In
1168:Small
1140:Large
1135:(70S)
1115:Small
1096:Large
1091:(55S)
1067:Small
1039:Large
997:Small
974:Large
940:Small
917:Large
792:Page
569:[
259:Size
194:ITS-2
186:ITS-1
1156:4.5S
1055:5.8S
1045:):
847:PMID
773:PMID
724:PMID
673:PMID
633:PMID
583:ISBN
541:PMID
448:and
436:and
395:rDNA
346:for
330:Uses
216:and
208:and
196:and
178:rDNA
153:The
118:and
98:and
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1174:):
1172:30S
1161:23S
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1144:50S
1078:18S
1073:):
1071:40S
1060:28S
1043:60S
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1008:16S
1003:):
1001:30S
990:23S
980:):
978:50S
965:(70
951:16S
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933:23S
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921:50S
908:(70
839:doi
796:on
765:doi
753:291
714:PMC
706:doi
665:doi
625:doi
613:239
575:doi
531:PMC
521:doi
390:.
358:of
350:by
338:in
218:ETS
206:28S
182:ETS
116:28S
94:in
86:in
70:in
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1151:5S
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
