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How dynamic could be the 45S rDNA cistron? An intriguing variability in a grasshopper species revealed by integration of chromosomal and genomic data. Chromosoma 2019; 128:165-175. [DOI: 10.1007/s00412-019-00706-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
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2
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Symonová R, Howell WM. Vertebrate Genome Evolution in the Light of Fish Cytogenomics and rDNAomics. Genes (Basel) 2018; 9:genes9020096. [PMID: 29443947 PMCID: PMC5852592 DOI: 10.3390/genes9020096] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/25/2018] [Accepted: 01/29/2018] [Indexed: 12/19/2022] Open
Abstract
To understand the cytogenomic evolution of vertebrates, we must first unravel the complex genomes of fishes, which were the first vertebrates to evolve and were ancestors to all other vertebrates. We must not forget the immense time span during which the fish genomes had to evolve. Fish cytogenomics is endowed with unique features which offer irreplaceable insights into the evolution of the vertebrate genome. Due to the general DNA base compositional homogeneity of fish genomes, fish cytogenomics is largely based on mapping DNA repeats that still represent serious obstacles in genome sequencing and assembling, even in model species. Localization of repeats on chromosomes of hundreds of fish species and populations originating from diversified environments have revealed the biological importance of this genomic fraction. Ribosomal genes (rDNA) belong to the most informative repeats and in fish, they are subject to a more relaxed regulation than in higher vertebrates. This can result in formation of a literal 'rDNAome' consisting of more than 20,000 copies with their high proportion employed in extra-coding functions. Because rDNA has high rates of transcription and recombination, it contributes to genome diversification and can form reproductive barrier. Our overall knowledge of fish cytogenomics grows rapidly by a continuously increasing number of fish genomes sequenced and by use of novel sequencing methods improving genome assembly. The recently revealed exceptional compositional heterogeneity in an ancient fish lineage (gars) sheds new light on the compositional genome evolution in vertebrates generally. We highlight the power of synergy of cytogenetics and genomics in fish cytogenomics, its potential to understand the complexity of genome evolution in vertebrates, which is also linked to clinical applications and the chromosomal backgrounds of speciation. We also summarize the current knowledge on fish cytogenomics and outline its main future avenues.
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Affiliation(s)
- Radka Symonová
- Faculty of Science, Department of Biology, University of Hradec Králové, 500 03 Hradec Králové, Czech Republic.
| | - W Mike Howell
- Department of Biological and Environmental Sciences, Samford University, Birmingham, AL 35229, USA.
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3
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Gong L, Shi W, Yang M, Kong X. Marked intra-genomic variation and pseudogenes in the ITS1-5.8S-ITS2 rDNA of Symphurus plagiusa (Pleuronectiformes: Cynoglossidae). ANIM BIOL 2018. [DOI: 10.1163/15707563-17000134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
The eukaryotic ribosomal DNA (rDNA) cluster consists of multiple copies of three genes (18S, 5.8S, and 28S rDNA) and two internal transcribed spacers (ITS1 and ITS2). In recent years, an increasing number of rDNA sequence polymorphisms have been identified in numerous species. In the present study, we provide 33 complete ITS (ITS1-5.8S-ITS2) sequences from two Symphurus plagiusa individuals. To the best of our knowledge, these sequences are the first detailed information on ITS sequences in Pleuronectiformes. Here, two divergent types (Type A and B) of the ITS1-5.8S-ITS2 rDNA sequence were found, which mainly differ in sequence length, GC content, nucleotide diversity (π), secondary structure and minimum free energy. The ITS1-5.8S-ITS2 rDNA sequence of Type B was speculated to be a putative pseudogene according to pseudogene identification criteria. Cluster analysis showed that sequences from the same type clustered into one group and two major groups were formed. The high degree of ITS1-5.8S-ITS2 sequence polymorphism at the intra-specific level indicated that the S. plagiusa genome has evolved in a non-concerted evolutionary manner. These results not only provide useful data for ribosomal pseudogene identification, but also further contribute to the study of rDNA evolution in teleostean genomes.
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Affiliation(s)
- Li Gong
- 1National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization, Zhejiang Ocean University, 316022, Zhoushan, China
- 2National Engineering Research Center for Facilitated Marine Aquaculture, Marine Science and Technology College, Zhejiang Ocean University, 316022, Zhoushan, China
| | - Wei Shi
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
| | - Min Yang
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
| | - Xiaoyu Kong
- 3Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong Provincial Key Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 510000, Guangzhou, China
- 4South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, 510000, Guangzhou, China
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4
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Barbosa P, Leal EV, da Silva M, de Almeida MC, Moreira-Filho O, Artoni RF. Variability and evolutionary implications of repetitive DNA dynamics in genome of Astyanax scabripinnis (Teleostei, Characidae). COMPARATIVE CYTOGENETICS 2017; 11:143-162. [PMID: 28919955 PMCID: PMC5599702 DOI: 10.3897/compcytogen.v11i1.11149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 12/30/2017] [Indexed: 06/11/2023]
Abstract
DNA sequences of multiple copies help in understanding evolutionary mechanisms, genomic structures and karyotype differentiation. The current study investigates the organization and distribution of different repetitive DNA in the standard complement and B chromosomes in Astyanax scabripinnis (Jenyns, 1842) chromosomes from three allopatric populations in Campos do Jordão region, São Paulo State, Brazil. The location of microsatellite sequences showed different chromosome distribution between Lavrinha Farm Stream (LFS) and Lake of Pedalinho (LP) populations. However, the karyotype of these populations basically followed the pattern of dispersed distribution in the A complement, conspicuous in telomeric/interstitial regions and preferential accumulation in the B chromosome. The B chromosome showed heterogeneous location of microsatellite probes CA, CAC and GA. The H3 and H4 histone genes were isolated from the total genome of the species and then the chromosomal mapping was performed by fluorescence in situ hybridization (FISH). The FISH signals showed high similarity for the probes H3 and H4 mapping in genomes of the populations analyzed. The sequences (GATA) n revealed a sex-specific trend between the chromosomal location in males and females at (LFS) and (LP) populations. Although species that comprise the Astyanax scabripinnis complex do not have morphologically differentiated sex chromosomes, the preferential GATA location - sex-associated - may represent a sex chromosome in differentiation.
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Affiliation(s)
- Patrícia Barbosa
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular, Universidade Federal de São Carlos, Rodovia Washington Luís Km 235, São Carlos, SP, 13565-905, Brazil
| | - Eliza Viola Leal
- Programa de Pós-Graduação em Biologia Evolutiva, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil
| | - Maelin da Silva
- Programa de Pós-Graduação em Biologia Evolutiva, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil
| | - Mara Cristina de Almeida
- Programa de Pós-Graduação em Biologia Evolutiva, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil
| | - Orlando Moreira-Filho
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular, Universidade Federal de São Carlos, Rodovia Washington Luís Km 235, São Carlos, SP, 13565-905, Brazil
- Programa de Pós-Graduação em Biologia Evolutiva, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil
| | - Roberto Ferreira Artoni
- Programa de Pós-Graduação em Genética Evolutiva e Biologia Molecular, Universidade Federal de São Carlos, Rodovia Washington Luís Km 235, São Carlos, SP, 13565-905, Brazil
- Programa de Pós-Graduação em Biologia Evolutiva, Universidade Estadual de Ponta Grossa, Avenida Carlos Cavalcanti 4748, Ponta Grossa, PR, 84030-900, Brazil
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5
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Kakou B, Angers B, Glémet H. Extensive length variation in the ribosomal DNA intergenic spacer of yellow perch (Perca flavescens). Genome 2016; 59:149-58. [PMID: 26841134 DOI: 10.1139/gen-2015-0114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intergenic spacer (IGS) is located between ribosomal RNA (rRNA) gene copies. Within the IGS, regulatory elements for rRNA gene transcription are found, as well as a varying number of other repetitive elements that are at the root of IGS length heterogeneity. This heterogeneity has been shown to have a functional significance through its effect on growth rate. Here, we present the structural organization of yellow perch (Perca flavescens) IGS based on its entire sequence, as well as the IGS length variation within a natural population. Yellow perch IGS structure has four discrete regions containing tandem repeat elements. For three of these regions, no specific length class was detected as allele size was seemingly normally distributed. However, for one repeat region, PCR amplification uncovered the presence of two distinctive IGS variants representing a length difference of 1116 bp. This repeat region was also devoid of any CpG sites despite a high GC content. Balanced selection may be holding the alleles in the population and would account for the high diversity of length variants observed for adjacent regions. Our study is an important precursor for further work aiming to assess the role of IGS length variation in influencing growth rate in fish.
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Affiliation(s)
- Bidénam Kakou
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada
| | - Bernard Angers
- b Department of Biological Sciences, Université de Montréal, Montréal, QC H3C 3J7, Canada.,c GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
| | - Hélène Glémet
- a Département des sciences de l'environnement, Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada.,c GRIL - Groupe de recherche interuniversitaire en limnologie et en environnement aquatique
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Śliwińska-Jewsiewicka A, Kuciński M, Kirtiklis L, Dobosz S, Ocalewicz K, Jankun M. Chromosomal characteristics and distribution of rDNA sequences in the brook trout Salvelinus fontinalis (Mitchill, 1814). Genetica 2015; 143:425-32. [PMID: 25958180 PMCID: PMC4486110 DOI: 10.1007/s10709-015-9841-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/04/2015] [Indexed: 11/09/2022]
Abstract
Brook trout Salvelinus fontinalis (Mitchill, 1814) chromosomes have been analyzed using conventional and molecular cytogenetic techniques enabling characteristics and chromosomal location of heterochromatin, nucleolus organizer regions (NORs), ribosomal RNA-encoding genes and telomeric DNA sequences. The C-banding and chromosome digestion with the restriction endonucleases demonstrated distribution and heterogeneity of the heterochromatin in the brook trout genome. DNA sequences of the ribosomal RNA genes, namely the nucleolus-forming 28S (major) and non-nucleolus-forming 5S (minor) rDNAs, were physically mapped using fluorescence in situ hybridization (FISH) and primed in situ labelling. The minor rDNA locus was located on the subtelo-acrocentric chromosome pair No. 9, whereas the major rDNA loci were dispersed on 14 chromosome pairs, showing a considerable inter-individual variation in the number and location. The major and minor rDNA loci were located at different chromosomes. Multichromosomal location (3-6 sites) of the NORs was demonstrated by silver nitrate (AgNO3) impregnation. All Ag-positive i.e. active NORs corresponded to the GC-rich blocks of heterochromatin. FISH with telomeric probe showed the presence of the interstitial telomeric site (ITS) adjacent to the NOR/28S rDNA site on the chromosome 11. This ITS was presumably remnant of the chromosome rearrangement(s) leading to the genomic redistribution of the rDNA sequences. Comparative analysis of the cytogenetic data among several related salmonid species confirmed huge variation in the number and the chromosomal location of rRNA gene clusters in the Salvelinus genome.
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Affiliation(s)
- A. Śliwińska-Jewsiewicka
- />Department of Human Histology and Embryology, Faculty of Medical Sciences, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - M. Kuciński
- />Department of Ichthyology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - L. Kirtiklis
- />Department of Zoology, Faculty of Biology and Biotechnology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
| | - S. Dobosz
- />Department of Salmonid Research, Inland Fisheries Institute in Olsztyn, Olsztyn, Poland
| | - K. Ocalewicz
- />Department of Marine Biology and Ecology, Faculty of Oceanography and Geography, University of Gdansk, Gdańsk, Poland
| | - Malgorzata Jankun
- />Department of Ichthyology, Faculty of Environmental Sciences, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland
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7
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Gornung E. Twenty years of physical mapping of major ribosomal RNA genes across the teleosts: A review of research. Cytogenet Genome Res 2013; 141:90-102. [PMID: 24080951 DOI: 10.1159/000354832] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Molecular cytogenetic data on the number and position of 45S ribosomal RNA genes (rDNA; located in nucleolus organizing regions, NORs) detected by FISH in 330 species of 77 families and 22 orders of bony fishes (Teleostei) and, additionally, 11 species of basal ray-finned fishes are compiled and analyzed. The portion of species with single rDNA sites in the sample amounts to 72%. The percentage of species with multiple NORs decreases with increasing numbers of rDNA loci per genome, i.e. scarcely 3% of species carry 4 or more rDNA-bearing chromosome pairs. 43% of all rDNA sites analyzed occur terminally on the short arms of chromosomes or constitute them. In general, terminal rDNA sites account for 87% of all examined cases. Interspecific variation in the location of single rDNA sites among related taxa, polymorphisms of multiple NORs in some groups of teleosts and analytical outcomes on the subject are reviewed.
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Affiliation(s)
- E Gornung
- 'Charles Darwin' Department of Biology and Biotechnologies, University of Rome 'La Sapienza', Rome, Italy
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Bauer N, Horvat T, Birus I, Vicić V, Zoldos V. Nucleotide sequence, structural organization and length heterogeneity of ribosomal DNA intergenic spacer in Quercus petraea (Matt.) Liebl. and Q. robur L. Mol Genet Genomics 2008; 281:207-21. [PMID: 19052776 DOI: 10.1007/s00438-008-0404-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Accepted: 11/08/2008] [Indexed: 11/29/2022]
Abstract
18S-5.8S-26S rDNA family comprises tandemly arranged, repeating units separated by an intergenic spacer (IGS) that contains transcription initiation/termination signals and usually repeating elements. In this study, we performed for the first time thorough sequence analysis of rDNA IGS region in two dominant European oaks, Quercus petraea and Q. robur, in order to investigate (1) if IGS sequence composition allows discrimination between these two species, and (2) if there is an rDNA length heterogeneity arising from IGS sequence. Two spacer length variants (slvs), 2 and 4 kb in length, were found in the genomes of both species. Inter-comparison of both slvs revealed no species-specificity in sequence or structural organization. Both slvs could be divided into four subregions; (1) the subrepeat region containing three repeated elements, (2) the AT-rich region containing matrix attachment sites and putative origin of replication, (3) the promoter region containing putative transcription initiation site and (4) the 5'ETS region. In the 4-kb slvs all four subregions are extended, and the subrepeat, AT-rich and promoter regions are duplicated. This is unique compared to other known IGS sequences where the variation in number of subrepeats is responsible for slvs creation. We also propose a possible evolutionary scenario to explain the formation of the subrepeat region in oak IGS. Results obtained in this work add to the previous picture of low-genetic differentiation of the two oaks and provide important data for further analyses of the function of IGS in control of rRNA gene expression.
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Affiliation(s)
- Natasa Bauer
- Department of Molecular Biology, University of Zagreb, Horvatovac, Zagreb, Croatia
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9
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Ghigliotti L, Mazzei F, Ozouf-Costaz C, Christiansen JS, Fevolden SE, Pisano E. First cytogenetic characterization of the sub-arctic marine fish Mallotus villosus (Müller, 1776), Osmeriformes, Osmeridae. Genet Mol Biol 2008. [DOI: 10.1590/s1415-47572008000200003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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10
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The two giant sister species of the Southern Ocean, Dissostichus eleginoides and Dissostichus mawsoni, differ in karyotype and chromosomal pattern of ribosomal RNA genes. Polar Biol 2006. [DOI: 10.1007/s00300-006-0222-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Korabecná M, Liska V, Fajfrlík K. Primers ITS1, ITS2 and ITS4 detect the intraspecies variability in the internal transcribed spacers and 5.8S rRNA gene region in clinical isolates of fungi. Folia Microbiol (Praha) 2003; 48:233-8. [PMID: 12800508 DOI: 10.1007/bf02930961] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Restriction fragment length polymorphism analysis of the 5.8S rRNA gene and the internal transcribed spacers (ITS1 and ITS2) was used for examination of 66 isolates belonging to 19 species. Intraspecies variability was found in the examined region of 11 species (Candida albicans, C. catenulata, C. colliculosa, C. glabrata, C. kefyr, C. melinii, C. parapsilosis, C. guillermondii, C. solanii, C. tropicalis, Saccharomyces cerevisiae). Region of ITS-5.8S rDNA was amplified using the primers ITS1 and ITS4. The amplicons were digested by HaeIII, HinfI and CfoI. The recognized intraspecies variability was confirmed in the second step, in which the shorter fragments of this region were amplified using primers ITS1 and ITS2 and analyzed by capillary electrophoresis. Considerable intraspecific variability renders this method unsuitable for species identification, whereas it can be useful for epidemiological tracing of isolates.
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Affiliation(s)
- M Korabecná
- Institute for Biology, Faculty of Medicine, Charles University, 301 66 Pilsen, Czechia.
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Reed KM, Hackett JD, Phillips RB. Comparative analysis of intra-individual and inter-species DNA sequence variation in salmonid ribosomal DNA cistrons. Gene 2000; 249:115-25. [PMID: 10831845 DOI: 10.1016/s0378-1119(00)00156-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study examines sequence divergence in three spacer regions of the ribosomal DNA (rDNA) cistron, to test the hypothesis of unequal mutation rates. Portions of two transcribed spacers (ITS-1 and 5' ETS) and the non-transcribed spacer (NTS) or intergenic spacer (IGS) formed the basis of comparative analyses. Sequence divergence was measured both within an individual lake trout (Salvelinus namaycush) and among several related salmonid species (lake trout; brook trout, Salvelinus fontinalis; Arctic char, Salvelinus alpinus; Atlantic salmon, Salmo salar; and brown trout, Salmo trutta). Despite major differences in the length of the rDNA cistron within individual lake trout, minimal sequence difference was detected among cistrons. Interspecies comparisons found that molecular variation in the rDNA spacers did not conform to the predicted pattern of evolution (ITS spacers<ETS spacers<IGS). Specifically, the IGS contains a region that appears to be as highly, or more conserved than the ITS-1.
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Affiliation(s)
- K M Reed
- Department of Biological Sciences, University of Wisconsin-Milwaukee, 53211, USA.
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