Heterochromatin

Karyotype description of two species of Hypostomus (Siluriformes, Loricariidae) of the Planalto da Bodoquena, Brazil

S. S. Cereali, Pomini, E., Rosa, R., Zawadzki, C. H., Froehlich, O., and Giuliano-Caetano, L., “Karyotype description of two species of Hypostomus (Siluriformes, Loricariidae) of the Planalto da Bodoquena, Brazil”, vol. 7, pp. 583-591, 2008.

Hypostomus sp 3-Córrego Salobrinha NUP 4247 and Hypostomus sp 2-Rio Perdido NUP 4249, collected in the Planalto da Bodoquena, Paraguay River basin, Brazil, were characterized cytogenetically. Hypostomus sp 3-Córrego Salobrinha showed two modal numbers. This polymorphism consists of the presence of two extrachromosomes. It was not possible to define the diploid number in four specimens, where cell lineages had 2n = 83 and 2n = 84 chromosomes in one individual, and 2n = 82, 2n = 83 and 2n = 84 chromosomes in the others.

Karyotypic variability in Iheringichthys labrosus (Teleostei, Pimelodidae) from the Tibagi River basin (Paraná State, Brazil)

L. B. Ribeiro, Matoso, D. A., Almeida, M. C., Vicari, M. R., Moraes-Neto, A., Svidnicki, M. C. C. M., and Artoni, R. F., “Karyotypic variability in Iheringichthys labrosus (Teleostei, Pimelodidae) from the Tibagi River basin (Paraná State, Brazil)”, vol. 7, pp. 718-724, 2008.

Cytogenetic analyses were carried out in a populational sample of Iheringichthys labrosus from the Guaraúna River (Upper Tibagi River; Paraná State, Brazil) in order to provide a karyotypic comparison with another previously studied population from the Lower Tibagi River, characterized by the presence of 32m + 8sm + 6st + 10a (2n = 56, FN = 102) and occurrence of supernumerary chromosomes (80% of individuals). The 17 specimens of I.

FISH analysis and cytogenetic characterization of male meiotic prophase I in Acricotopus lucidus (Diptera, Chironomidae)

W. Staiber, “FISH analysis and cytogenetic characterization of male meiotic prophase I in Acricotopus lucidus (Diptera, Chironomidae)”, vol. 8, pp. 1218-1230, 2009.

In the chironomid Acricotopus lucidus, two cells with quite different chromosome complements arise from the last unequal spermatogonial mitosis, as a consequence of monopolar migration of the so-called germ line limited chromosomes (Ks). The cell receiving all the Ks, in addition to two sets of the regularly segregating somatic chromosomes (Ss), develops into the primary spermatocyte, while the cell getting only Ss differentiates into an aberrant spermatocyte. Only the primary spermatocyte enters meiosis. These nuclear events in the primary spermatocytes of A.

Composition of constitutive heterochromatin of Pseudonannolene strinatii Mauriès, 1974 (Diplopoda, Spirostreptida) analyzed by AT/CG specific fluorochromes

K. Agari Campos and Fontanetti, C. Silvia, “Composition of constitutive heterochromatin of Pseudonannolene strinatii Mauriès, 1974 (Diplopoda, Spirostreptida) analyzed by AT/CG specific fluorochromes”, vol. 4, pp. 765-770, 2005.

Triple staining with fluorochromes (DA/DAPI/CMA) and C-banding were used to characterize the composition of Pseudonannolene strinatii heterochromatin. C-banding showed C+ bands of different labeling intensity on chromosomes 1 and 2 in some cells. Fluorochrome staining revealed DAPI+ regions corresponding to the C-banding pattern, indicating that the heterochromatin of this species is abundant in AT-rich sequences.