Full text in pdf format

Cytogenetic studies in six species of tropiduridae (Sauria)

Katia Cristina Machado Pellegrino^I; Yatiyo Yonenaga-Yassuda^I; Miguel Trefaut Rodrigues^II

^IDepartamento de Biologia, Instituto de Biociências, USP, Caixa Postal 11461, 05422-970 São Paulo, SP, Brasil. Send correspondence to Y.Y.-Y.
^IIDepartamento de Zoologia, Instituto de Biociências, USP, São Paulo, SP, Brasil

ABSTRACT

Cytogenetic studies were performed on six tropidurid lizards: Tropidurus mucujensis, T. hispidus, T montanus, T. semitaeniatus, T. spinulosus and Uranoscodon superciliosus. Conventional and differential (C- and R-bands and Ag-NORs) staining techniques were employed for the characterization of the karyotypes.
The analyses were carried out in order to establish the morphological characterization of macro and microchromosomes, the R- and C-banding patterns as well as the silver staining of nucleolus organizer regions (Ag-NORs). R-banding was obtained after in vitro incorporation of 5-bromodeoxyuridine (BrdU). For some species, the banding patterns are described for the first time.
All species presented a diploid number of 2n=36, with a basic karyotype constituted by 12 metacentric or submetacentric macrochromosomes and 24 microchromosomes (12M+24m). Although these species present a conservative karyotype, most of them are distinguished by the morphology of the macro and microchromosomes, by location of Ag-NORs, and by amount and distribution of constitutive heterochromatin. Sex determination of the XX:XY type was found in T. hispidus, T. montanus and U. superciliosus. The presence of species specific karyotypes in T. spinulosus and U. superciliosus is suggested.

Keywords: cytogenetic studies; tropiduridae.

REFERENCES

Bickham, J.W. (1984). Patterns and modes of chromosomal evolution in reptiles. In: Chromosomes in Evolution of Eukaryotic Groups, Vol. II (Sharma, A.K. and Sharma, A., eds.). CRC Press, Florida, pp. 13-39.

Dutrillaux, B. and Couturier, J. (1981). La Pratique del'Analyse Chromosomique. Masson, Paris, pp. 88.

Frost, D.R. (1992). Phylogenetic analysis and taxonomy of Tropidurus group of lizards (Iguania: Tropiduridae). Am. Mus. Novit. 3033: 1-68.

Frost, D.R. and Etheridge, R.A. (1989). Phylogenetic analysis and taxonomy of iguanian lizards (Reptilia: Squamata). Misc. Publ., Univ. Kan. Mus. Nat. Hist. 81: 1-65.

Gorman, G.C. (1973). The chromosomes of the Reptilia, cytotaxonomic interpretation. In: Cytotaxonomy and Vertebrate Evolution (Chiarelli, A.B. and Cappana, E., eds.). Academic Press, New York, pp. 349-424.

Howell, W.M. and Black, D.A. (1980). Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method. Experientia 36: 1014-1015.

Kasahara, S., Yonenaga-Yassuda, Y., Schincariol, R.A. and L'Abbate, M. (1983). Chromosome mechanisms of sex determination, G- and C-band patterns and nucleolus organizer regions in Tropidurus torquatus (Sauria, Iguanidae). Genetica 60: 151-156.

Kasahara, S., Yonenaga-Yassuda, Y. and Rodrigues, M.T. (1987a). Geographical karyotypic variations and chromosome banding patterns in Tropidurus hispidus (Sauria, Iguanidae) from Brazil. Caryologia 40: 43-57.

Kasahara, S., Yonenaga-Yassuda, Y. and Rodrigues, M.T. (1987b). Karyotype and evolution of the Tropidurus nanuzae species group (Sauria, Iguanidae). Rev. Brasil. Genet. 10: 185-197.

Kasahara, S., Yonenaga-Yassuda, Y. and Rodrigues, M.T. (1989). Caracterização cromossômica de 11 espécies de Tropidurus do grupo torquatus (Sauria: Iguanidae). IX Congresso Latino Americano de Genética, Peru, 1-5 outubro. Resumenes: 162.

Paull, D., Williams, E.E. and Hall, W.P. (1976). Lizard karyotypes from the Galapagos islands: chromosomes in phylogeny and evolution. Breviora 441: 1-31.

Porter, C.A., Meredith, J.H., Sites Jr., J.W. and Baker, R.J. (1991). Location of ribosomal DNA in chromosomes of squamate reptiles: systematic and evolutionary implications. Herpetologica 47: 271-280.

Porter, C.A., Haiduk, M.W. and Queiroz, K. (1994). Evolution and phylogenetic significance of ribosomal gene location in chromosomes of squamate reptiles. Copeia 1994: 302-313.

Rodrigues, M.T., Yonenaga-Yassuda, Y. and Kasahara, S. (1989). Notes on the ecology and karyotypic description of Strobilurus torquatus (Sauria, Iguanidae). Rev. Brasil. Genet. 12: 747-759.

Sumner, A.T. (1972). A simple technique for demonstrating centromeric heterochromatin. Exptl. Cell Res. 75: 304-306.

Yonenaga-Yassuda, Y., Kasahara, S., Chu, T.H. and Rodrigues, M.T. (1988). High-resolution RBG-banding pattern in the genus Tropidurus (Sauria, Iguanidae). Cytogenetic. Cell Genet. 48: 68-71.