High Dynamics of rDNA Cluster Location in Kissing Bug Holocentric Chromosomes (Triatominae, Heteroptera)

Abstract

In this paper, we determine by fluorescent in situ hybridization the variability in the chromosomal location of 45S rDNA clusters in 38 species belonging to 7 genera of the Triatominae subfamily, using a triatomine-specific 18S rDNA probe. Our results show a striking variability at the inter- and intraspecific level, never reported so far in holocentric chromosomes, revealing the extraordinary genomic dynamics that occurred during the evolution in this group of insects. Our results also demonstrate that the chromosomal position of rDNA clusters is an important marker to disclose chromosomal differentiation in species karyotypically homogenous in their chromosome number.

Chromosomal divergence and evolutionary inferences in Rhodniini based on the chromosomal location of ribosomal genes

“…Two localisation patterns were revealed: either on both sex chromosomes (X and Y chromosomes) (8 species) or only on the X chromosome (4 species), with one species presenting both patterns (R. ecuadoriensis) (Figs 1, 2, Table). The number of rDNA loci was consistent with other Triatominae species, with the detection of up to two loci (see Panzera et al 2012 for a review). In the Triatomini tribe, or within the genus Triatoma, the ribosomal genes showed four different chromosomal positions, including autosomes bearing 45S rDNA ).…”

“…FISH -The FISH assays were conducted using squashed gonad preparations that had previously been fixed in 3:1 ethanol:acetic acid, as described by Panzera et al (2012). A DNA plasmid harbouring an 807-bp region of the 18S rDNA gene of Triatoma infestans (accession Y18750) was used as a probe; the probe was labelled using the Nick Translation System (Invitrogen, Carlsbad, California, USA) with Cy3-dUTP (GE Healthcare, Life Sciences, Oregon, USA).…”

Physical mapping of 18S rDNA and heterochromatin in species of family Lygaeidae (Hemiptera: Heteroptera)

“…Oncopeltus femoralis showed an 18S rDNA interstitial site in an autosomal bivalent; Ochrimnus sagax showed this sequence in the largest autosomal bivalent in the interstitial terminal region, whereas, in Lygaeus peruvianus, the rDNA cistrons were found in the interstitial region of an autosomal pair. In Heteroptera, studies focusing on the identification and localization of 18S rDNA on chromosomes are restricted to a few species of some families and the results have shown that the 18S rRNA gene might be located in both the autosomes and the sex chromosomes (Papeschi et al, 2003;Bardella et al, 2010;Grozeva et al, 2010;Poggio et al, 2011;Panzera et al, 2012). However, most of the studies revealed that these cistrons at terminal position of the chromosomes were different from those found in the species analyzed in this study.…”

“…In Hemiptera, these studies have revealed important findings compared to those obtained in other groups of insects (Caterino et al, 2000). Besides 18S rDNA, other classes of repetitive DNA with heterochromatic sequences have also been widely used as cytogenetic markers for comparisons across different groups of insects such as in Orthoptera (Cabral-de-Mello et al, 2011), Coleoptera (Almeida et al, 2010), Diptera (Rafael et al, 2006), and Heteroptera Bardella et al, 2010;Grozeva et al, 2010;Panzera et al, 2012). Some types of repetitive DNA can be chromosomespecific, such as those mostly found in Drosophila melanogaster (Bonaccorsi and Lohe, 1991) and those found on the sex chromosomes in species such as Megoura (Bizzaro et al, 1996).…”

Distribution of constitutive heterochromatin in Triatoma melanocephala (Hemiptera, Triatominae)

“…However, experimental crosses , molecular (Mendonça et al, 2009;Gardim et al, 2014), enzymatic (Costa et al, 1997), and cytogenetic (Panzera et al, 2010(Panzera et al, , 2012Alevi et al, 2012aAlevi et al, , 2013aSucci et al, 2014) techniques have been used as important tools to aid in the classification of species.…”