Highly divergent karyotypes and barcoding of the East African genus Gonatoxia Karsch (Orthoptera: Phaneropterinae)

Abstract

East Africa is a hotspot of biodiversity of many orthopteran taxa, including bushcrickets. Gonatoxia Karsch, 1889 species are fully alate Phaneropterinae, which are perfectly adapted to the foliage of forests. We examined five species using combined cytogenetic and molecular data to determine the inter- and intraspecific genetic diversity. The variation in the diploid number of chromosomes in males ranged from 2n = 28 + X0 and 26 + X0 to 2n = 6 + X0. Fluorescence in situ hybridization showed from one to many 18S rDNA loci as well as interstitial sequences, especially in G. helleri. 18S rDNA loci coincided with active NOR and C-banding patterns. The isolation of populations of the species explains differences in the number of chromosomes (G. maculata), chromosomal polymorphism and chromosomal heterozygosity (G. helleri). Our molecular phylogeny based on the COI locus supported the monophyly of the genus Gonatoxia and separateness of the five examined species in accordance with their morphological features and chromosome numbers as well as the species’ distribution.

Telomere organization and the interstitial telomeric sites involvement in insects and vertebrates chromosome evolution

“…In other species with 2n = 17, no ITS were observed on large metacentric rearranged chromosomes ( Jetybayev et al, 2012 ). In the Tettigoniidae Gonatoxia helleri, the occurrence of ITS on all chromosomes seems to be in concordance with points of fusion and inversion rearrangements ( Warchałowska-Śliwa et al, 2021 ).…”

“…However, only a few ITS cases containing loci of (TTAGG) n were detected (see references below), even in species with highly rearranged karyotypes. They are limited to few species, representatives of orders Lepidoptera ( Rego and Marec, 2003 ), Hemiptera ( Chirino et al, 2017 ), and Orthoptera ( López-Fernández et al, 2004 ; Jetybayev et al, 2012 , 2017 ; Camacho et al, 2015 ; Grzywacz et al, 2019 ; Buleu et al, 2020 ; Warchałowska-Śliwa et al, 2021 ).…”

“…Among insects, Orthoptera is the group with most ITS cases described until now, with occurrence in more than 20 species. The ITS were noticed in species belonging to multiple groups, including representatives of Tettigoniidae, Pamphagidae, and Acrididae ( López-Fernández et al, 2004 ; Jetybayev et al, 2012 , 2017 ; Camacho et al, 2015 ; Grzywacz et al, 2019 ; Buleu et al, 2020 ; Warchałowska-Śliwa et al, 2021 ). In this last group, it was present on some representatives from subfamily Gomphocerinae and in Podisma pedestris (Cantatopinae), Eyprepocnemis plorans (Eyprepocneminae), and Schistocerca gregaria (Cyrtacanthacridinae) ( Figure 6B ).…”

“…On Pamphagidae, multiple species with neo-XY harbor ITS on the pericentromeric region of neo-X, as a consequence of chromosome fusion between an ancestral autosome and the X chromosome ( Jetybayev et al, 2017 ), although pericentric inversions could also be involved in the posterior origin of the ITS ( Buleu et al, 2020 ). ITS on ancestral X chromosome from X0/XX sex system was scarcely observed ( Buleu et al , 2020 ; Warchałowska-Śliwa et al, 2021 ). Finally, in multiple species of Orthoptera with neo-sex system, although resultant of fusion chromosome rearrangements no ITS are noticed, suggesting that the Rb fusions involved the loss of telomeres, originated from double chromosome breaks or the ITS were eliminated later along sex chromosomes differentiation.…”

New insights into the genetic diversity of the Balkan bush-crickets of the Poecilimon ornatus group (Orthoptera: Tettigoniidae)

“…The cytochrome c oxidase subunit I (COI) gene is a commonly used marker, easy to amplify due to the availability of conserved primers, with a strong phylogenetic signal, used in taxonomy (Folmer et al 1994;Simon et al 1994Simon et al , 2006Spicer 1995;Zhang and Hewitt 1997;Goto and Kimura 2001;Remigio and Hebert 2003;Kjer et al 2014;Wang et al 2017;Jafari et al 2019;Karmazina et al 2020). This marker is successfully used in Orthoptera and treated as a DNA barcode (Lehmann et al 2017;Kaya and Çıplak 2018;Kundu et al 2020;Liu and He 2021;Şirin et al 2021;Warchałowska-Śliwa et al 2021). NADH dehydrogenase subunit 2 (ND2) shows a higher proportion of variable and parsimony-informative sites (PI) and a lower heterogeneity of the substitution index than COI (Cheng et al 2018), which was confirmed in Isophya -a closely related genus to Poecilimon (Chobanov et al 2017), and in Hematopoecilimon .…”