Bed bug cytogenetics: karyotype, sex chromosome system, FISH mapping of 18S rDNA, and male meiosis in Cimex lectularius Linnaeus, 1758 (Heteroptera: Cimicidae)

Abstract

Abstract. Bugs (Insecta: Heteroptera) are frequently used as examples of unusual cytogenetic characters, and the family Cimicidae is one of most interest in this respect. We have performed a cytogenetic study of the common bed bug Cimex lectularius Linnaeus, 1758 using both classical (Schiff-Giemsa and AgNO 3 -staining) and molecular cytogenetic techniques (base-specifi c DAPI/CMA 3 fl uorochromes and FISH with an 18S rDNA probe). Males originated from a wild population of C. lectularius were found to have 2n = 26 + X 1 X 2 Y, holokinetic chromosomes, 18S rRNA genes located on the X 1 and Y chromosomes; achiasmate male meiosis of a collochore type; MI and MII plates nonradial and radial respectively.

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).…”

“…These studies revealed the distribution of 18S rDNA sites in autosomal chromosomes, such as those observed in Pachylis argentinus Berg, 1879, and Nezara viridula Linnaeus, 1758 (Papeschi et al, 2003), as well as in sex chromosomes such as those of the families Belostomatidae , Cimicidae (Grozeva et al, 2010), and Reduviidae (Bardella et al, 2010). Although studies investigating the location of heterochromatin are more common in Heteroptera, most of them are restricted to conventional analyses such as C-banding technique .…”

Chromosomal location of rDNA clusters and TTAGG telomeric repeats in eight species of the spittlebug genus Philaenus (Hemiptera: Auchenorrhyncha: Aphrophoridae)

“…Most probably the observed differences reflect variation in the copy number of rRNA genes either between different chromosome pairs or between two homologous chromosomes. This can be attributed to various mechanisms, including unequal crossing over, transposition, tandem amplification and other rearrangements involving homologous segments, yielding structural modification of NORs (Castro et al, 2001) The heteromorphism in size and intensity of NORs has been frequently reported in aphids (Monti et al, 2011 and reference therein), heteropterans (Grozeva et al, 2010), orthopterans (Warchałowska-Śliwa et al, 2009), as well as certain other insect orders.…”

Comparison of different cytogenetic methods and tissue suitability for the study of chromosomes in Cimex lectularius (Heteroptera, Cimicidae)

“…Leston 1957, Piza 1957, Warren et al 1960, Ueshima 1963 and it is still considered as a classical method by the majority of insect cytogeneticists including heteropterologists (e.g. Bressa et al 2002a, Poggio et al 2006, Grozeva et al 2010, Yang et al 2012.…”