The nucleotide sequences of the 5S rRNA multigene family and their distribution across the karyotypes in 2 species of Gymnotiformes, genus Gymnotus (G. sylvius and G. inaequilabiatus) were investigated by means of fluorescence in situ hybridization (FISH). The results showed the existence of 2 distinct classes of 5S rDNA sequences in both species: class I and class II. A high conservative pattern of the codifying region of the 5S rRNA gene was identified, contrasting with significant alterations detected in the nontranscribed spacer (NTS). The presence of TATA-like sequences along the NTS of both species was an expected occurrence, since such sequences have been associated with the regulation of the gene expression. FISH using 5S rDNA class I and class II probes revealed that both gene classes were collocated in the same chromosome pair in the genome of G. sylvius, while in that of G. inaequilabiatus, class II appeared more disperse than class I.

1.
Albert JS, Crampton WG, Thorsen DH, Lovejoy NR: Phylogenetic systematics and historical biogeography of the neotropical electric fish Gymnotus (Teleostei: Gymnotidae). Syst Biodiv 4:375–417 (2005).
2.
Alves-Costa FA, Wasko AP, Oliveira C, Foresti F, Martins C: Genomic organization and evolution of the 5S ribosomal DNA in Tilapiini fishes. Genetica 127:243–252 (2006).
3.
Campo D, Machado-Schiaffino G, Horreo JL, Garcia-Vazquez E: Molecular organization and evolution of 5S rDNA in the genus Merluccius and their phylogenetic implications. J Mol Evol 68:208–216 (2009).
4.
Cioffi MB, Martins C, Bertollo LA: Chromosome spreading of associated transposable elements and ribosomal DNA in the fish Erythrinus erythrinus. Implications for genome change and karyoevolution in fish. BMC Evol Biol 10:271–280 (2010).
5.
Fernandes-Matioli FM, Marchetto MC, Almeida-Toledo LF, Toledo-Filho SA: High intraspecific karyological conservation in four species of Gymnotus (Pisces: Gymnotiformes) from southeastern Brazilian basins. Caryologia 3:221–234 (1998).
6.
Fernandes-Matioli FM, Albert J, Daniel-Silva MF, Lopes CE, Crampton WG, Almeida-Toledo LF: A new Gymnotus (Teleostei: Gymnotiformes: Gymnotidae) from the Pantanal Matogrossense of Brazil and adjacent drainages: continued documentation of a cryptic fauna. Zootaxa 933:1–14 (2005).
7.
Foresti F, Torres RA, Toledo-Filho SA: Chromosome studies in Gymnotus carapo and Gymnotus sp. (Pisces, Gymnotidae). Caryologia 37:141–146 (1984).
8.
Foresti F, Oliveira C, Almeida-Toledo LF: A method for chromosome preparations from large specimens of fishes using in vitro short treatment with colchicine. Experientia 49:810–813 (1993).
9.
Fujiwara M, Inafuku J, Takeda A, Watanabe A, Fujiwara A, et al: Molecular organization of 5S rDNA in bitterlings (Cyprinidae). Genetica 10.1007/s10709-008-9294-2 (2008).
10.
Hall TA: BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows 95/98/NT. Nucl Acids Symp Ser 41:95–98 (1999).
11.
Kimura M: A simple method for estimating evolutionary rate of base substitution through comparative studies of nucleotide sequences. J Mol Evol 16:111–120 (1980).
12.
Levan A, Fredga K, Sandberg AA: Nomenclature for centromeric position on chromosomes. Hereditas 52:201–220 (1964).
13.
Long EO, David IB: Repeated genes in Eukaryotes. Ann Rev Biochem 49:727–764 (1980).
14.
Martins C, Galetti PM Jr: Two rDNA arrays in Neotropical fish species: is it a general rule for fishes? Genetica 111:439–446 (2001).
15.
Martins C, Wasko AP: Organization and evolution of 5S ribosomal DNA in the fish genome, in Williams CR (ed): Focus on Genome Research, pp 335–363 (Nova Science Publishers, Hauppauge, NY 2004).
16.
Milhomem SS, Pieczarka JC, Crampton WG, Souza AC, Carvalho JR Jr, Nagamachi CY: Differences in karyotype between two sympatric species of Gymnotus (Gymnotiformes: Gymnotidae) from the eastern Amazon of Brazil. Zootaxa 1397:55–62 (2007).
17.
Milhomem SS, Pieczarka JC, Crampton WG, Silva DS, Souza AC, et al: Chromosomal evidence for a cryptic species in the Gymnotus carapo species-complex (Gymnotiformes, Gymnotidae). BMC Evol Biol 9:75 (2008).
18.
Milhomem SS, Crampton WG, Pieczarka JC, Shetka GH, Silva DS, Nagamachi CY: Gymnotus capanema, a new species of electric knife fish (Gymnotidae-Gymnotiformes) from eastern Amazonia, with comments on an unusual karyotype. J Fish Biol (in press) (2011).
19.
Morescalchi MA, Liguori I, Rocco L, Archimandritis A, Stingo V: Karyotypic characterization and genomic organization of the 5S rDNA in Polypterus senegalus (Osteichthyes, Polypteridae). Genetica 132:179–186 (2008).
20.
Nederby-Nielsen J, Hallenberg C, Frederiksen S, Sorensen PD, Lomholt B: Transcription of human 5S rRNA genes is influenced by an upstream DNA sequence. Nucl Acids Res 26:3631–3636 (1993).
21.
Pendás AM, Móran P, Freije JP, Garcia-Vásquez E: Chromosomal location and nucleotide sequence of two tandemrepeats of the Atlantic salmon 5S rDNA. Cytogen Cell Genet 67:31–36 (1994).
22.
Pendás AM, Morán P, Martínez JL, Garcia-Vásquez E: Applications of 5S rDNA in Atlantic salmon, brown trout, and in Atlantic salmon × brown trout hybrid identification. Mol Ecol 4:275–276 (1995).
23.
Pinhal D, Araki CS, Gadig OB, Martins C: Molecular organization of 5S rDNA in sharks of the genus Rhizoprionodon: insights into the evolutionary dynamics of 5S rDNA in vertebrate genomes. Genet Res 91:61–72 (2009).
24.
Pinkel D, Straume T, Gray JW: Cytogenetic analysis using quantitative, high-sensitivity, fluorescence hybridization. Proc Natl Acad Sci USA 83:2934–2938 (1986).
25.
Sánchez S, Laudicina A, Jorge LC: A new report of multiple sex chromosome system in the order Gymnotiformes (Pisces). Cytologia 69:155–160 (2004).
26.
Scacchetti PC, Pansonato-Alves JC, Utsunomia R, Oliveira C, Foresti F: Karyotypic diversity in four species of the genus Gymnotus Linnaeus, 1758 (Teleostei, Gymnotiformes, Gymnotidae): physical mapping of ribosomal genes and telomeric sequences. Comp Cytogen 5:223–235 (2011).
27.
Silva EB, Margarido VP: An X1X1X2X2/X1X2Y multiple sex chromosome system in a new species of the genus Gymnotus (Pisces, Gymnotiformes). Environ Biol Fishes 73:293–297 (2005).
28.
Thompson JD, Gibson TJ, Plewniak F, Jeanmougin F, Higgins DG: The ClustalX windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools. Nucleic Acids Res 24:4876–4882 (1997).
29.
Xia X, Xie Z: DAMBE: data analysis in molecular biology and evolution. J Hered 92:371–373 (2001).
30.
Zhu HP, Lu MX, Gao FY, Huang ZH, Yang LP, Gui JF: Chromosomal localization of rDNA genes and genomic organization of 5S rDNA in Oreochromis mossambicus, O. urolepis hornorum and their hybrid. J Genet 89:163–171 (2010).
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