Abstract
The organization of the repeat unit of the ribosomal genes was determined in populations of Odontophrynus americanus 2n, 4n, O. occidentalis 2n and O. barrioi 2n (Amphibia, Anura) from South America. HindIII, EcoRI and BamHI restriction patterns of rDNA from single individuals were probed with two rDNA clones from Xenopus laevis. Variations in length and sequence were found among different species, populations and specimens. A general pattern could be established from the most frequent type of repeat observed in each case, so that diploid populations could be distinguished from tetraploid ones. The molecular evolution of variant repeats is discussed. It is suggested that the reduced size of the non-transcribed spacers in the tetraploids from São Paulo could play a role in the control of rDNA transcription. Distinct restriction maps were tentatively correlated to the varying localization of active rDNA clusters on metaphase chromosomes of corresponding populations.
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Abbreviations
- kb :
-
kilobase
- ITS :
-
internal transcribed spacer
- NTS :
-
non-transcribed spacer
- K :
-
kidney
- B :
-
blood
- NOR :
-
nucleolar organizer region
- rDNA :
-
ribosomal DNA
- rRNA :
-
ribosomal RNA
- S :
-
Svedberg unit
- SSC :
-
sodium saline citrate
References
Almeida TMB, Ruiz IRG, Beçak W (1986) Ribosomal gene activity detected by silver staining in two diploid populations of Odontophrynus americanus (Amphibia, Anura) from Southern Brazil Rev Bras Genet 9:433–437
Beçak ML, Beçak W (1974) Studies on polyploid amphibians: karyotype evolution and phylogeny of the genus Odontophrynus. J Herpetol 8:337–341
Beçak W, Goissis G (1971) DNA and RNA content in diploid and tetraploid amphibians. Experientia 27:345–346
Bruns PJ, Katzen AL, Martin L, Blackburn EH (1985) A drugresistant mutation in the ribosomal DNA of Tetrahymena. Proc Natl Acad Sci USA 82:2844–2846
Busslinger M, Hurst J, Flavell RA (1983) DNA methylation and the regulation of globin gene expression. Cell 34:197–206
Cei JM, Ruiz IRG, Beçak W (1982) Odontophrynus barrioi a new species of Amphibia Anura from Argentina. J Herpetol 16:97–102
Cortadas J, Pavon MC (1982) The organization of ribosomal genes in vertebrates. EMBO J 1:1075–1080
Dover GA (1982) Molecular drive: a cohesive mode of species evolution. Nature 299:111–117
Dover GA, Flavell RB (1984) Molecular coevolution: DNA divergence and the maintenance of function. Cell 38:622–623
Labhart P, Reeder RH (1986) Characterization of three sites of RNA 3' end formation in the Xenopus ribosomal gene spacer. Cell 45:431–443
Lima-de-Faria A (1976) The chromosome field. I. Prediction of the location of ribosomal cistrons. Hereditas 83:1–22
Lima-de-Faria A (1983) Molecular evolution and organization of the chromosome. Elsevier, New York, p 1186
Long B, Dawid IB (1980) Repeat genes in eukaryotes. Annu Rev Biochem 49:727–764
McStay B, Reeder RH (1986) A termination site for Xenopus RNA polymerase I also acts as an element of an adjacent promoter. Cell 47:913–920
Meunier-Rotival M, Cortadas J, Macaya G, Bernardi G (1979) Isolation and organization of calf ribosomal DNA. Nucleic Acids Res 6:2109–2123
Pan W-C, Orias E, Flacks M, Blackburn EH (1982) Allele-specific selective amplification of a ribosomal RNA gene in Tetrahymena thermophila. Cell 28:595–604
Reeder RH (1984) Enhancers and ribosomal gene spacers. Cell 38:349–351
Reeder RH, Roan JG (1984) The mechanism of nucleolar dominance in Xenopus hybrids. Cell 38:39–44
Rigby PWJ, Dieckmann M, Rhodes C, Berg P (1977) Labeling deoxyribonucleic acid to high specific activity in vitro by nick translation with polymerase I. J Mol Biol 113:237–251
Ruiz IRG, Soma M, Beçak W (1981) Nucleolar organizer regions and constitutive heterochromatin in polyploid species of the genus Odontophrynus (Amphibia, Anura). Cytogenet Cell Genet 29:84–98
Ruiz IRG, Cei JM, Beçak W (1982) Chromosomal evolution in allopatric populations of Odontophrynus occidentalis group (Amphibia, Anura) from Western Argentina. Cytogenet Cell Genet 33:303–311
Ruiz IRG, Almeida TMB, Beçak W (1984) Active nucleolar organizer regions in polyploid populations of O. americanus (Amphibia, Anura) from South Brazil. Genetica 63:31–37
Southern EM (1980) Gel electrophoresis of restriction fragments. Methods Enzymol 68:165–176
Ware VC, Tague BW, Clark CG, Gourse RL, Brand RC, Gerbi SA (1983) Sequence analysis of 28S ribosomal DNA from the amphibian Xenopus laevis. Nucleic Acids Res 11:7795–7817
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Dr. Jordi Cortadas passed away 29th August 1985. He had last been working at Instituto de Biologia de Barcelona, Spain
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Cortadas, J., Ruiz, I.R.G. The organization of ribosomal genes in diploid and tetraploid species of the genus Odontophrynus (Amphibia, Anura). Chromosoma 96, 437–442 (1988). https://doi.org/10.1007/BF00303038
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DOI: https://doi.org/10.1007/BF00303038