Variability of 18rDNA loci in four lace bug species (Hemiptera, Tingidae) with the same chromosome number

Abstract

Male karyotypes of Elasmotropis testacea (Herrich-Schaeffer, 1835), Tingis cardui (Linnaeus, 1758), Tingis crispata (Herrich-Schaeffer, 1838), and Agramma femorale Thomson, 1871 (Heteroptera, Cimicomorpha, Tingidae) were analyzed using conventional chromosome staining and FISH with 18S rDNA and (TTAGG)n telomeric probes. The FISH technique was applied for the first time in the Tingidae. In spite of the fact that all species showed the same chromosome number (2n = 12 + XY), they have significant differences in the number and position of rDNA loci. FISH with the classical insect (TTAGG)n probe produced no signals on chromosomes suggesting telomeres in lace bugs to be of some other molecular composition. Tingidae share absence of the (TTAGG)n telomeric sequence with all so far studied taxa of the advanced true bug infraorders Cimicomorpha and Pentatomomorpha.

Chromosomal evolutionary dynamics of four multigene families in Coreidae and Pentatomidae (Heteroptera) true bugs

“…Genome dynamics for repetitive DNAs in pentatomids was previously proposed by analysis of different amplification patterns of A + T or G + C C-bands in the genus Edessa (Bardella et al 2014). A similar situation occurs within the Heteroptera suborder in the Reduviidae subfamily, in which the karyotype 2n = 20 + XY is maintained in most representatives of Triatoma and in four species of Tingidae lace bugs with 2n = 12 + XY, but with variation in the number and position of 18S rDNA clusters (Panzera et al 2012;Golub et al 2015). For Acrididae grasshoppers in related species with the same chromosome number, a high dynamics for the number and location of 5S rDNA clusters was noticed, with these patterns attributed to amplification, association with transposable elements and movement through extrachromosomal circular DNA (eccDNA) (Cabral-de-Mello et al 2011b), which are mechanisms that may operate in the Heteroptera genomes.…”

“…In the suborder Heteroptera, which comprises approximately 40,000 species with holocentric chromosomes (Ueshima 1979;Weirauch and Schuh 2011), the mapping of multigene families is restricted to 18S rDNA (Panzera et al 2012; Bardella et al 2013;Chirino et al 2013;Golub et al 2015). Among the infraorders studied, the data have revealed diversity in the number and location of clusters in Triatoma, and conservation in the genus Rhodnius (Reduviidae, Cimicomorpha) (Panzera et al 2012;Pita et al 2013).…”

Comparative cytogenetics and derived phylogenic relationship among Sitophilus grain weevils (Coleoptera, Curculionidae, Dryophthorinae)

“…zeamais and in S. linearis , respectively. Transposition of genes to new locations, inversions, translocations, ectopic recombination, transposable elements and hybridization without a change in chromosome number are all mechanisms that have already been used to explain this variation in the localization of rDNA genes (Cabrero and Camacho 2008, Panzera et al 2012, Pita et al 2013, Golub et al 2015, Vershinina et al 2015). Thus, results presented here show that rDNA loci may be considered an important cytogenetic marker for this genus and that cytogenetic analysis on different populations and/or other Sitophilus species will certainly contribute to a better understanding of mechanisms responsible for their ribosomal loci variation.…”

“…In this context, base-specific fluorochromes and fluorescent in situ hybridization (FISH) with different ribosomal DNA probes allow a more detailed analysis of the molecular structure of chromosomes, and reveal many more differences among closely related species than conventional techniques (Bione et al 2005, Silva et al 2009, Cabral-de-Mello et al 2010, 2011). As an example, the identification of rRNA clusters in different species has been widely used in comparative cytogenetics to understand the patterns of karyotypic evolution in different taxonomic groups (Cuadrado et al 2008, Cabral-de-Mello et al 2011, Cioffi et al 2011, Grozeva et al 2011, Golub et al 2015, Palacios-Gimenez and Cabral-de-Mello 2015). …”

Karyotypes and Repetitive DNA Evolution in Six Species of the Genus <b><i>Mahanarva </i></b>(Auchenorrhyncha: Cercopidae)

“…The (TTAGG) n motif is canonical and considered ancestral for insects and arthropods as a whole [Sahara et al, 1999;Frydrychová et al, 2004], although it has been variably lost during the evolution of some orders, such as Diptera, Coleoptera, Hymenoptera, and Hemiptera [Sahara et al, 1999;Frydrychová et al, 2004;Gokhman et al, 2014]. Among hemipterans, the apomorphic heteropterans Cimicomorpha (families Miridae, Cimicidae, and Tingidae) and Pentatomomorpha (families Pyrrhocoridae and Pentatomidae) lost the (TTAGG) n ancestral motif [Frydrychová et al, 2004;Grozeva et al, 2011;Golub et al, 2015]. However, (TTAGG) n was not lost in other groups, including 4 aphid species [Monti et al, 2011], in the coccid Planococcus li- lacinus [Mohan et al, 2011], in the suborder Coleorrhyncha , in the heteropteran infraorder Nepomorpha , and in Auchenorrhyncha representatives [Frydrychová et al, 2004;Maryańska-Nadachowska et al, 2012;Golub et al, 2014;Kuznetsova et al, 2015b].…”