New evidence for the presence of the telomere motif (TTAGG) n in the family Reduviidae and its absence in the families Nabidae and Miridae (Hemiptera, Cimicomorpha)

Abstract

Male karyotype and meiosis in four true bug species belonging to the families Reduviidae, Nabidae, and Miridae (Cimicomorpha) were studied for the first time using Giemsa staining and FISH with 18S ribosomal DNA and telomeric (TTAGG)n probes. We found that Rhynocoris punctiventris (Herrich-Schäffer, 1846) and R. iracundus (Poda, 1761) (Reduviidae: Harpactorinae) had 2n = 28 (24 + X1X2X3Y), whereas Nabis sareptanus Dohrn, 1862 (Nabidae) and Horistus orientalis (Gmelin, 1790) (Miridae) had 2n = 34 (32 + XY) and 2n = 32 (30 + XY), respectively. FISH for 18S rDNA revealed hybridization signals on a sex chromosome, the X or the Y, in H. orientalis, on both X and Y chromosomes in N. sareptanus, and on two of the four sex chromosomes, Y and one of the Xs, in both species of Rhynocoris Hahn, 1834. The results of FISH with telomeric probes support with confidence the absence of the “insect” telomere motif (TTAGG)n in the families Nabidae and Miridae and its presence in both species of genus Rhynocoris of the Reduviidae, considered as a basal family of Cimicomorpha. Increasing evidence reinforces the hypothesis of the loss of the canonical “insect” telomere motif (TTAGG)n by at least four cimicomorphan families, Nabidae, Miridae, Tingidae, and Cimicidae, for which data are currently available.

Jekyll or Hyde? The genome (and more) of Nesidiocoris tenuis, a zoophytophagous predatory bug that is both a biological control agent and a pest

“…Screening of the genome and Southern blot assay suggest the absence of the ancestral insect telomere motif, (TTAGG) n , in N. tenuis , as the case in other species from the family Miridae (Kuznetsova et al ., 2011; Grozeva et al ., 2019). The telomeric motif was present in our Tandem Repeat Finder results, but in much lower numbers than expected for telomeric sequences.…”

“…Initially, we searched both the raw sequencing data and the assembled genome for presence of the ancestral insect telomere motif (TTAGG) n , which is known to be absent in several Miridae (Grozeva et al ., 2019; Kuznetsova et al ., 2011), and tested for its presence using Southern dot blot in N. tenuis . gDNA was isolated from N. tenuis , and positive controls E. kuehniella and T. infestans , using CTAB DNA isolation described above.…”

“…The absence of the ancestral TTAGG n telomeric repeat has been reported for mirids Macrolophus spp., Deraeocoris spp. and Megaloceroea recticornis (Geoffroy) (Jauset et al ., 2015; Grozeva et al ., 2011, 2019) but more knowledge of this trait is necessary for evolutionary studies of genomes and karyotypes. Furthermore, the taxonomic issues that lie within both Miridae and Hemiptera could better be resolved using protein and transcriptome‐based analysis, but there is a noted lack of data in this regard as well (Panfilio and Angelini, 2018).…”

New data on karyotype, spermatogenesis and ovarian trophocyte ploidy in three aquatic bug species of the families Naucoridae, Notonectidae, and Belostomatidae (Nepomorpha, Heteroptera)

“…In Heteroptera, adults are traditionally used for cytogenetic studies as at this stage, accurate species identification is easy and spermatogenesis still occurs (e.g. Nokkala and Nokkala 1999, Grozeva and Nokkala 2003, Lanzone and Souza 2006, Castanhole et al 2008, Golub et al 2018, Grozeva et al 2019, for extensive bibliography see Papeschi and Bressa 2006). However, in last (V) instar and adults of nepomorphan species I. cimicoides and N. glauca, testes were shown to con-tain only spermatids/spermatozoa.…”

Comparative FISH mapping of ribosomal DNA clusters and TTAGG telomeric sequences to holokinetic chromosomes of eight species of the insect order Psocoptera

“…Our knowledge of karyotype structure and evolution in Psocoptera could be improved by the implementation of molecular cytogenetic approaches. Fluorescence in situ hybridization (FISH) has become the most important technique for tracing individual chromosomes in holokinetic insects (e.g., Panzera et al 2012, 2015, Maryańska-Nadachowska et al 2013, 2018, Mandrioli et al 2014, Kuznetsova et al 2015, Anjos et al 2016, Golub et al 2017, Salanitro et al 2017, Grozeva et al 2019). It was shown in some case studies that species with the same chromosome complement differ in the number and location of rDNA sites (Panzera et al 2012, 2015, Maryańska-Nadachowska et al 2013, Golub et al 2017).…”