Cytogenetic analysis of Ctenostomini by C-banding and rDNA localization and its relevance to the knowledge of the evolution of tiger beetles (Coleoptera: Cicindelidae)

Abstract.A cytogenetic study of bisexual species belonging to the genera Cirrorhynchus, Dodecastichus and Otiorhynchus is presented in order to confirm their taxonomic position. The karyotype characterization was accomplished by an analysis of mitotic and meiotic chromosomes after differential staining, namely by C-banding, silver impregnation, DAPI and CMA3. A review of the cytogenetic data for the tribe Otiorhynchini contributed to knowledge of chromosomal evolution in this group. An investigation of five of the species studied showed some similarities such as a sex chromosome system of "parachute type" (Xyp), the presence of 10 autosomal bivalents (2n = 22) and heterochromatin localized around centromeres. These observations are similar to those already described for Otiorhynchini species, and confirm the karyological conservatism of this weevil group. In contrast, another species Cirrorhynchus kelecsenyi has an additional four autosomal bivalents (n% = 14 + Xyp, 2n = 30), which differs considerably from the chromosomal homogeneity of the other genera. Karyotypic evolution in this species was achieved most probably by increasing the number of chromosomes by centric fissions, resulting in variation in the number of acrocentric chromosomes. DAPI-positive and CMA3-negative reactions of heterochromatic DNA in all the species studied suggest that it has an AT-rich composition. Impregnating chromosomes with silver nitrate reveals NORs on one pair of autosomes, and probably argentophilic material in the interspace between the X and y sex chromosomes. The karyological findings support the taxonomical revision of Otiorhynchini based on morphological characters.

Section: Discussionmentioning

confidence: 96%

Cytotaxonomy and karyology of the tribe Otiorhynchini (Coleoptera: Curculionidae)

Lachowska¹,

Rozek²,

Holecová³

2008

“…The distribution of constitutive heterochromatin has been described for different families and subfamilies of Coleoptera, in which the C-bands are generally located in the pericentromeric region of the autosomal chromosomes (Vidal et al, 1977;Virkki, 1983;Juan & Petitpierre, 1989;Rozek & Lachowska, 2001;Zacaro et al, 2004;Bione et al, 2005;Almeida et al, 2009). The chromosomes of Chrysomelidae also exhibited this pattern (Virkki, 1983;Almeida et al, 2006Almeida et al, , 2009Mello et al, 2014); however, they show a lower amount of heterochromatin compared with other groups, such as Elateridae and Tenebrionidae (Juan & Petitpierre, 1989;Rozek et al, 2004;Schneider et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Comparative cytogenetic analysis in 13 tortoise beetles (Coleoptera: Chrysomelidae: Cassidinae) from Brazil

Lopes¹,

Fernandes²,

Schneider³

2016

ISSN (online): 1802-8829http://www.eje.cz fi nding was corroborated by a phylogenetic study using molecular data (Gómez-Zurita et al., 2008).Cytogenetically, only 117 Cassidinae species belonging to 13 tribes have been investigated to date (for revision see De Julio et al., 2010). The tortoise beetles are considered as a group with conserved karyotype, in which approximately 52% of the analyzed species showed 2n = 16 + Xy p , with metacentric and/or submetacentric chromosomes (De Julio et al., 2010). However, cytogenetic records also demonstrated that the diploid numbers can range from 2n = 16 to 2n = 51, as well the sex chromosome systems, which can be either simple -Xy p , X0, Xy, Xy c , Xy r , neoXY, or multiple -Xyy p , X p neoXneoY p , X p neoXneoy p , neoX p neoyy p , neoX p1 neoX p2 neoXneoy p , neoX p1 neoX p2 neoXneoy, X p1 X p2 -neoXneoy (for review see De Julio et al., 2010). These variations in the diploid number and sex chromosome systems are more or less frequent according to the tribe considered. In Cassidini and Mesomphaliini, 44% and 100% Abstract. In the present work, we have characterized the chromosomes of 13 Cassidinae beetles, belonging to four tribes, the broad aim being to increase the cytogenetic data and establish the mechanisms involved in chromosome evolution of this subfamily, which appear to be conserved karyotypically, i.e. 2n = 16 + Xy p . The analysis of mitotic and meiotic cells revealed a high diversity of diploid numbers (2n = 18, 2n = 22, 2n = 26, 2n = 32, 2n = 36, 2n = 40, 2n = 42), and the presence of sex chromosome system of the Xy p type in most species, with the exception of two representatives that exhibited Xy r and XY systems. C-banding showed constitutive heterochromatin predominantly localized in the pericentromeric region of the chromosomes, but differences regarding the number of chromosomes with positive C-bands, intensity of the blocks, and presence of additional bands in autosomes and/or sex chromosomes were observed among the species investigated. Our data revealed that the karyotype 2n = 16 + Xy p does not occur in all 13 tribes of the Cassidinae characterized cytogenetically, seeming to be only a shared feature among the species of the Cassidini. Variations in the C-band pattern, mainly in closely related species, suggest that the interspecifi c karyotype diversifi cation occurred as a result of changes in the quantity and distribution of constitutive heterochromatin. The occurrence of the Xy p sex chromosome system in the tribe Mesomphaliini, which showed the highest diversity of simple and multiple systems among the coleopteran as a whole, reinforces the view that derived systems originated by chromosome rearrangements involving the Xy p ancestral system.

“…Ribosomal genes (rDNA) are useful for comparing the karyotypes of insect species at the genus level, e.g. in tiger beetles (Zacaro et al, 2004), grasshoppers (e.g. Loreto et al, 2008), and tettigonids (Warchaowska-liwa et al, 2009;Hemp et al, 2010).…”

Section: Cytogenetic Characterization and Karyotype Evolutionmentioning

confidence: 99%

Changes in the numbers of chromosomes and sex determination system in bushcrickets of the genus Odontura (Orthoptera: Tettigoniidae: Phaneropterinae)

Warchałowska‐Śliwa¹,

Maryańska-Nadachowska²,

Grzywacz³

et al. 2011

Abstract.Chromosomes of the males of five species of Odontura, belonging to the subgenera Odontura and Odonturella, were analyzed. Intensive evolution of the karyotype was recorded, both in terms of changes in the numbers of chromosomes (from 2n = 31 to 27) and the sex chromosome system (from X0 to neo-XY and X0 to neo-X1X2Y). Karyotype evolution was accompanied by tandem autosome fusions and interspecific autosomal and sex chromosome differentiation involving changes in the locations of nucleolar organizer regions, NORs, which were revealed by silver impregnation and confirmed by FISH using an 18S rDNA probe. O. (Odonturella) aspericauda is a polytypic species with X0 and neo-X1X2Y sex determination. The latter system is not common in tettigoniids. It possibly originated by a translocation of a distal segment of the original X chromosome onto a medium sized autosome, resulting in a shortened neo-X1 and a metacentric neo-Y. The remaining autosome homologue became the neo-X2 chromosome. This shift from X0 to neo-X1X2Y is supported by the length of the X chromosome and location of the NOR/rDNA.