Karyotype Variability in the Genus Radacridium (Orthoptera, Romaleidae, Romaleinae).

A Comparative Cytogenetic Analysis between the Grasshopper Species Chromacris nuptialis and C. speciosa (Romaleidae): Constitutive Heterochromatin Variability and rDNA Sites

“…Karyotypes of C. nuptialis and C. speciosa resemble those reported for other Chromacris species and for most romaleid species, as to chromosome number (2n = 23,X0 and 2n = 24,XX) and morphology (acrocentric) (Mesa, Ferreira & Carbonell, 1982;Souza & Kido, 1995;Rocha, Souza & Tashiro, 1997). One exception to this uniformity has been described for Xestotrachelus robustus (2n = 23,X0 and 2n = 24,XX), a species taxonomically related to Chromacris, where the S 9 and S 10 pairs are meta-submetacentric and probably originated from a pericentric inversion, since the rearrangement did not change the chromosome number of the species (Souza,Haver & Figure 3.…”

“…Additionaly, ocurrence of interstitial and distal blocks has been reported for Xyleus angulatus (Souza & Kido, 1995;Souza, Rufas & Orellana, 1998), Radacridium mariajoseae, R. nordestinum (Rocha, Souza & Tashiro, 1997), and Chromacris speciosa (Souza & Kido, 1995). Polymorphisms for supernumerary heterochromatic segments have been described for X. angulatus (Souza & Silva-Filha, 1993) and R. nordestinum (Rocha, Souza & Tashiro, 1997) and B chromosomes have been observed in X. angulatus (Souza & Kido, 1995) and Zoniopoda tarsata (Vilardi, 1986), proving the intensive variability in CH, among representatives of this family.…”

Chromosome study in Schistocerca (Orthoptera-Acrididae-Cyrtacanthacridinae): karyotypes and distribution patterns of constitutive heterochromatin and nucleolus organizer regions (NORs)

“…al., 2005). Other grasshoppers of the genera Calliptamus, Oeidipoda, Euchorthippus and Radacridium also differed in their C-banding patterns (Rocha et al, 1997;Santos et al, 1983).…”

Chromosomal characterization of Pseudonannolene strinatii (Spirostreptida, Pseudonannolenidae)

“…In Orthoptera, it has been suggested that the constitutive heterochromatin plays a role in the protection of NORs, since the NOR is of main importance in protein synthesis throughout the cell cycle (SENTIS et al, 1986;WARCHALOWSKA-SLIWA & MARYANSKA-NADACHOWSKA, 1992;W.-SLIWA & BULGROV, 1997;ROCHA et al, 1997). In anuran amphibians, it has been proposed that these C+ blocks next to the NORs restrict genetic recombination to their flanking regions, impeding the formation of chiasmas or forcing their formation in other regions (SCHMID, 1982).…”