Abstract
Five species belonging to the genus Gampsocleis Fieber, 1852 were analyzed using fluorescence in situ hybridization (FISH) with 18S rDNA and telomeric probes, as well as C-banding, DAPI/CMA3 staining and silver impregnation. The studied species showed two distinct karyotypes, with 2n = 31 (male) and 2n = 23 (male) chromosomes. The drastic reduction in chromosome number observed in the latter case suggests multiple translocations and fusions as the main responsible that occurred during chromosome evolution. Two groups of rDNA distribution were found in Gampsocleis representatives analyzed. Group 1, with a single large rDNA cluster on the medium-sized autosome found in four species, carried in the haploid karyotype. Group 2, represented only by G.abbreviata, was characterized by the presence of two rDNA signals. TTAGG telomeric repeats were found at the ends of chromosome arms as expected. The rDNA clusters coincided with active NORs and GC-rich segments.
Highlights
The Gampsocleis Fieber, 1852 belongs to Gampsocleidini Brunner von Wattenwyl, 1893, a relatively small tribe of Tettigoniinae Krauss, 1902, which includes 17 currently recognized species and 7 subspecies mainly distributed in the Palearctic region (Cigliano et al 2018)
The standard karyotype of G. gratiosa, G. sedakovii sedakovii and G. ussuriensis was characterized by a chromosome number of 2n = 31
In four species we detected a single large rDNA cluster on a medium-sized autosome. This was and G. ussuriensis (b) studied using different techniques: fluorescence in situ hybridization (FISH) with both 18S rDNA and telomeric TTAGG probes (a) in diakinesis revealed a single rDNA locus located distally on the 6th bivalent and one active nucleolus organizer regions (NORs) visualized by AgNO3 staining (b) in diplotene
Summary
The Gampsocleis Fieber, 1852 belongs to Gampsocleidini Brunner von Wattenwyl, 1893, a relatively small tribe of Tettigoniinae Krauss, 1902, which includes 17 currently recognized species and 7 subspecies mainly distributed in the Palearctic region (Cigliano et al 2018). Molecular phylogenetic studies on Gampsocleis have shown the taxonomic problem (Zhang et al 2011, Zhou et al 2011). We focus on molecular and classical cytogenetics, providing data on the karyotype structure and evolution of the group. Changes in chromosome number (karyotype variability) or structure can contribute to speciation (e.g. Dion-Côté et al 2017; Gould et al 2017). Information on cytogenetic markers is useful for understanding the chromosomal organization and assessing the karyotype diversity of organisms. In this sense, chromosome rearrangements, such as Robertsonian fusions and inversions, can be important in tettigoniid karyotype evolution and could have a role as drivers in the speciation process (Warchałowska-Śliwa 1998)
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