Comparative analysis of chromosomes in the Palaearctic bush-crickets of tribe Pholidopterini (Orthoptera, Tettigoniinae)

Abstract

The present study focused on the evolution of the karyotype in four genera of the tribe Pholidopterini: Eupholidoptera Mařan, 1953, Parapholidoptera Mařan, 1953, Pholidoptera Wesmaël, 1838, Uvarovistia Mařan, 1953. Chromosomes were analyzed using fluorescence in situ hybridization (FISH) with 18S rDNA and (TTAGG)n telomeric probes, and classical techniques, such as C-banding, silver impregnation and fluorochrome DAPI/CMA3 staining. Most species retained the ancestral diploid chromosome number 2n = 31 (male) or 32 (female), while some of the taxa, especially a group of species within genus Pholidoptera, evolved a reduced chromosome number 2n = 29. All species show the same sex determination system X0/XX. In some taxa, a pericentric inversion has changed the morphology of the ancestral acrocentric X chromosome to the biarmed X. The rDNA loci coincided with active NORs and C-band/CG-rich segments. A comparison of the location of the single rDNA/NOR in the genus Pholidoptera suggests that reduced chromosome number results from Robertsonian translocation between two pairs of autosomes, one carrying the rDNA/NOR. The results constitute a step towards better understanding of the chromosomal reorganization and evolution within the tribe Phaneropterini and the whole subfamily Tettigoniinae.

Tribal affiliation of endemic Macaronesian bush-crickets similar to Tettigonia (Orthoptera: Tettigoniidae) based on their karyology and taxonomy

“…A similar type of translocation is reported in some other species of Tettigoniinae (e.g. Grzywacz et al, 2017a;Warchałowska-Śliwa et al, 2005Warchałowska-Śliwa et al, , 2017. In addition, the present and previous studies indicate that the karyotypes of Tettigonia are stable and there are no changes in the chromosome number and general morphology of the X chromosome in this genus.…”

“…A single bivalent carrying the 18S rDNA cluster, but in the interstitial or paracentromeric regions, is reported in other tettigoniids, e.g. in European Platycleidini (Grzywacz et al, 2017a) and Pholidopterini (Warchałowska-Śliwa et al, 2017). Furthermore, one active NOR appears to be a typical feature of karyotypes of European Tettigoniinae (Warchałowska-Śliwa et al, 2005).…”

“…The terminal locations of hybridization signals in Psalmatophanes, Calliphona and Tettigonia indicate that the telomeres are composed of (TTAGG) n repeats as in other Orthoptera (e.g. Warchałowska-Śliwa et al, 2011Warchałowska-Śliwa et al, , 2013Warchałowska-Śliwa et al, , 2017Grzywacz et al, 2014). The number and morphology of chromosomes and marker differentiation did not differ in Psalmatophanes barettoi, Calliphona koenigi and Tettigonia.…”

“…Recently the location of ribosomal genes were studied in order to understand genomic differentiation and distinguish between species and evolutionary lines in some bush-crickets of the subfamily Tettigoniinae (Grzywacz et al, 2017a;Warchałowska-Śliwa et al, 2017). One rDNA/ NOR locus (per haploid genome) is coincident with a single active NOR and GC-rich heterochromatin region located near the distal part of the second pair of chromosomes.…”

A Comparative Chromosome Mapping Study in Japanese Podismini Grasshoppers (Orthoptera: Acrididae: Melanoplinae)

“…Probably, a lack of tDNA-FISH signal in some chromosomes could explain the low number of telomeric copies. Similar results have been reported in other Orthoptera species [Warchałowska-Śliwa et al, 2013[Warchałowska-Śliwa et al, , 2017. Previous studies have suggested that (TTAGG) n was a phylogenetically ancestral telomere motif in Hexapoda but was lost independently in different groups [Sahara et al, 1999;Frydrychová et al, 2004].…”