Chromosome mapping in Abracris flavolineata (De Geer, 1773) (Orthoptera) from the Iguaçu National Park – Foz do Iguaçu, Paraná, Brazil

Abstract

In this paper, we present the cytomolecular analysis of a population of Abracris flavolineata collected in the largest fragment of the Brazilian Atlantic forest, the Iguaçu National Park. The diploid number in males was 23 (22+X0), with two large pairs (1–2), 7 medium (3–9), 2 small (10–11) and the X chromosome of medium size. Heterochromatic blocks were evident in the pericentromeric regions of all chromosomes. Heterogeneity in the distribution of heterochromatin was observed, with a predominance of DAPI+ blocks. However, some chromosomes showed CMA3+ blocks and other DAPI+/CMA3+ blocks. The 18S rDNA sites were distributed on the short arms of 5 pairs. In two of these pairs, such sites were in the same chromosome bearing 5S rDNA, and one of the bivalents, they were co-located. Histone H3 genes were found on one bivalent. The results added to the existing cytogenetic studies provided evidence of great karyotypic plasticity in the species. This pliancy may be the result of vicariant events related to the geographical distribution of different populations of A. flavolineata.

Cytogenetic markers applied to cytotaxonomy in two soybean pests: Anticarsia gemmatalis (Hübner, 1818) and Chrysodeixis includens (Walker, 1858)

“…This differentiation of heterochromatic blocks detected both by the C-band technique and by the coloration of base-specific fluorochromes may result from heterochromatinization processes or the presence of transposable elements. These events have previously been suggested in studies where there were differences in the presence of intra-and inter-specific heterochromatic blocks in grasshopper populations [37,38] and in beetles [39]. In addition to protecting the genome from potentially mutagenic events, heterochromatin formation suggests that they are crucial sequences for the functional organization of important chromosomal structures, such as telomeres and centromeres [40], relating it to the karyotype of evolutionary studies.…”

Insights on repetitive DNA behavior in two species of Ctenus Walckenaer, 1805 and Guasuctenus Polotow and Brescovit, 2019 (Araneae, Ctenidae): Evolutionary profile of H3 histone, 18S rRNA genes and heterochromatin distribution

“…[9]. In C. ornatus and G. longipes, secondary constrictions were shown to be associated to 18S rDNA, and this type of association is recurrent in several animal groups, such as the grasshopper Abracris flavolineata De Geer 1773 [25] and the fish Loricariichthys platymetopon Isbrücker and Nijssen, 1979 [26].…”

Insights into the karyotype evolution and speciation of the beetle Euchroma gigantea (Coleoptera: Buprestidae)

“…Dispersion of histone sequences was also observed in grasshoppers (Oliveira et al 2011;Bueno et al 2013). However, dispersion in E. gigantea was found in all different karyotypes, unlike orthopterans, which present variation in number of sites among individuals within a species with a single karyotype (Oliveira et al 2011;Bueno et al 2013;Pine et al 2017). Dispersion of histone genes is generally attributed to mechanisms that maintain highly repetitive sequences in centromeric regions, such as mobility of transposable elements, ectopic recombination, or extrachromosomal circular DNA (eccDNA), which are also proposed to explain the dispersion of other classes of repetitive DNA (Fitch et al 1990;Raskina et al 2004;Bione et al 2005;Cohen et al 2010;Nguyen et al 2010).…”