Physical mapping of 5S rDNA in 2 species of knifefishes, Gymnotuspantanal and G. paraguensis (Gymnotiformes), was performed using fluorescence in situ hybridization with a 5S rDNA probe. The 5S rDNA PCR product from the genomes of both species was also sequenced and aligned to determine non-transcribed spacer sequences (NTS). Both species under study had different patterns of 5S rDNA gene cluster distribution. While in the karyotype of G. pantanal two 5S rDNA-bearing pairs were observed, the karyotype of G. paraguensis possessed as many as 19 such pairs. Such multiplication of 5S rDNA gene clusters might be caused by the involvement of transposable elements because the NTS of G. paraguensis was 400 bp long with high identity (90%) with a mobile transposable element called Tc1-like transposon, described from the cyprinid fish Labeo rohita.

1.
Albert JS, Crampton WG, Thorsen DH, Lovejoy NR: Phylogenetic systematics and historical biogeography of the neotropical electric fish Gymnotus (Teleostei, Gymnotidae). System Biodivers 2:375–417 (2005).
2.
Altschul SF, Gish W, Miller W, Myers EW, Lipman DJ: Basic local alignment search tool. J Mol Biol 215:403–410 (1990).
3.
Baum BR, Johnson DA: The 5S DNA sequences in Hordeum bogdonii and the H. brevisubulatum complex, and the evolution and the geographic dispersal of the diploid Hordeum species (Triticeae: Poaceae). Genome 50:1–14 (2007).
4.
Bertollo LA, Takahashi CS, Moreira-Filho O: Cytotaxonomic considerations on Hoplias lacerdae (Pisces, Erythrinidae). Braz J Genet 1:103–120 (1978).
5.
Campos-da-Paz R: Family Gymnotidae; in Reis RE, Kullander SO, Ferraris CJ Jr (eds): Check List of the Freshwater Fishes of South and Central America, pp 483–486 (Edipucrs, Porto Alegre 2003).
6.
Claro FL: Gymnotus carapo e Gymnotus sylvius (Teleostei: Gymnotidae): uma abordagem citogenética-molecular (Master Thesis, Universidade de São Paulo, 2008).
7.
Cognato D, Richer-de-Forges MM, Albert JS, Crampton WG: Gymnotus chimarrao, a new species of electric fish (Gymnotiformes: Gymnotidae) from Southern Brazil. Ichthyol Explor Fres 18:375–382 (2007).
8.
Goodier JL, Davidson WS: Tc1 transposon-like sequences are widely distributed in salmonids. J Mol Biol 24:26–34 (1994).
9.
Hart S, Koch KR, Woods DR: Identification of indigo-related pigments produced by Escherichia coli containing a cloned Rhodococcus gene. J Genet Microbiol 138:211–216 (1992).
10.
Kidwell MG, Lisch DR: Transposable elements and host genome evolution. Trends Ecol Evol 15:95–99 (2000).
11.
Komiya H, Takemura S: Nucleotide sequence of 5S ribosomal RNA from rainbow trout (Salmo gairdnerii) liver. J Biochem 86:1067–1080 (1979).
12.
Krasnov A, Koskinen H, Afanasyev S, Mölsä H: Transcribed Tc1-like transposons in salmonid fish. BMC Genomics 6:1–10 (2005).
13.
Lacerda MC, Maistro E: Cytogenetic analysis of three sympatric Gymnotus species (Teleostei: Gymnotidae) from the Fundo stream, MG, Brazil. Cytologia 72:89–93 (2007).
14.
Leaver MJ: A family of Tc1-like transposons from the genomes of fishes and frogs: evidence for horizontal transmission. Gene 271:203–214 (2001).
15.
Levan A, Fredga K, Sandberg AA: Nomenclature for centromeric position on chromosomes. Hereditas 52:201–220 (1964).
16.
Margarido VP, Bellafronte E, Moreira-Filho O: Cytogenetic analysis of three sympatric Gymnotus (Gymnotiformes, Gymnotidae) species verifies invasive species in the Upper Paraná River basin, Brazil. J Fish Biol 70:155–164 (2007).
17.
Martins C, Galetti PM Jr: Chromosomal localization of 5S rDNA genes in Leporinus fish (Anostomidae, Characiformes). Chromosome Res 7:363–367 (1999).
18.
Martins C, Galetti PM Jr: Organization of 5S rDNA in species of the fish Leporinus: two different genomic locations are characterized by distinct nontranscribed spacers. Genome 44:903–910 (2001).
19.
Martins C, Wasko AP: Organization and evolution of 5S ribosomal DNA in the fish genome; in Williams CR (ed): Focus on Genome Research (Nova Science Publishers, Hauppauge, 2004).
20.
Maxime EL, Albert JS: A new species of Gymnotus (Gymnotiformes: Gymnotidae) from the Fitzcarrald Arch of southeastern Peru. Neotrop Ichthyol 7:579–585 (2009).
21.
Murray MG, Thompson WF: Rapid isolation of high molecular weight plant DNA. Nucl Acids Res 8:4321–4326 (1980).
22.
Nei M, Rooney AP: Concerted evolution and birth-and-death evolution of multigene families. Ann Rev Genet 39:121–152 (2005).
23.
Pinkel D, Straume T, Gray JW: Cytogenetic analysis using quantitative, high-sensitivity, fluorescence hybridization. Proc Natl Acad Sci USA 83:2934–2938 (1986).
24.
Plasterk RH, Izsvak Z, Ivics Z: Resident aliens: the Tc1/mariner superfamily of transposable elements. Trends Genet 15:326–332 (1999).
25.
Quackenbush J, Cho J, Lee D, Liang F, Holt I, et al: The TIGR Gene Indices: analysis of gene transcript sequences in highly sampled eukaryotic species. Nucl Acids Res 29:159–170 (2001).
26.
Richer-de-Forges MM, Crampton WG, Albert JS: A new species of Gymnotus (Gymnotiformes, Gymnotidae) from Uruguay: description of a model species in neurophysiological research. Copeia 3:538–544 (2009).
27.
Sambrook J, Russell DW: Molecular cloning: a laboratory manual (Cold Spring Harbor Press, New York 2001).
28.
Thompson JD, Higgins DG, Gibson TJ: CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choice. Nucl Acids Res 22:4673–4680 (1994).
29.
Wasko AP, Martins C, Wright JM, Galetti PM Jr: Molecular organization of 5S rDNA in fishes of the genus Brycon. Genome 44:893–902 (2001).
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.