Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)

Tandem arrays of TTAGG repeats show a highly conserved location at the telomeres across the phylogenetic tree of arthropods. In giant water bugs Belostoma, the chromosome number changed during speciation by fragmentation of the single ancestral X chromosome, resulting in a multiple sex chromosome sy...

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Autor principal:	Bressa, Maria Jose
Publicado:	2017
Materias:	chromosomal fusion interstitial telomeric repeats karyotype evolution telomere FISH
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20457758_v7_n14_p5227_Chirino http://hdl.handle.net/20.500.12110/paper_20457758_v7_n14_p5227_Chirino
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	paper:paper_20457758_v7_n14_p5227_Chirino
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spelling	paper:paper_20457758_v7_n14_p5227_Chirino2025-07-30T19:09:18Z Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma) Bressa, Maria Jose chromosomal fusion interstitial telomeric repeats karyotype evolution telomere FISH Tandem arrays of TTAGG repeats show a highly conserved location at the telomeres across the phylogenetic tree of arthropods. In giant water bugs Belostoma, the chromosome number changed during speciation by fragmentation of the single ancestral X chromosome, resulting in a multiple sex chromosome system. Several autosome–autosome fusions and a fusion between the sex chromosome pair and an autosome pair resulted in the reduced number in several species. We mapped the distribution of telomeric sequences and interstitial telomeric sequences (ITSs) in Belostoma candidulum (2n = 12 + XY/XX; male/female), B. dentatum (2n = 26 + X1X2Y/X1X1X2X2), B. elegans (2n = 26 + X1X2Y/X1X1X2X2), B. elongatum (2n = 26 + X1X2Y/X1X1X2X2), B. micantulum (2n = 14 + XY/XX), and B. oxyurum (2n = 6 + XY/XX) by FISH with the (TTAGG)n probes. Hybridization signals confirmed the presence of TTAGG repeats in the telomeres of all species examined. The three species with reduced chromosome numbers showed additional hybridization signals in interstitial positions, indicating the occurrence of ITS. From the comparison of all species here analyzed, we observed inverse relationships between chromosome number and chromosome size, and between presence/absence of ITS and chromosome number. The ITS distribution between these closely related species supports the hypothesis that several telomere–telomere fusions of the chromosomes from an ancestral diploid chromosome number 2n = 26 + XY/XX played a major role in the karyotype evolution of Belostoma. Consequently, our study provide valuable features that can be used to understand the karyotype evolution, may contribute to a better understanding of taxonomic relationships, and also elucidate the high plasticity of nuclear genomes at the chromosomal level during the speciation processes. © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Fil:Bressa, M.J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2017 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20457758_v7_n14_p5227_Chirino http://hdl.handle.net/20.500.12110/paper_20457758_v7_n14_p5227_Chirino
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	chromosomal fusion interstitial telomeric repeats karyotype evolution telomere FISH
spellingShingle	chromosomal fusion interstitial telomeric repeats karyotype evolution telomere FISH Bressa, Maria Jose Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
topic_facet	chromosomal fusion interstitial telomeric repeats karyotype evolution telomere FISH
description	Tandem arrays of TTAGG repeats show a highly conserved location at the telomeres across the phylogenetic tree of arthropods. In giant water bugs Belostoma, the chromosome number changed during speciation by fragmentation of the single ancestral X chromosome, resulting in a multiple sex chromosome system. Several autosome–autosome fusions and a fusion between the sex chromosome pair and an autosome pair resulted in the reduced number in several species. We mapped the distribution of telomeric sequences and interstitial telomeric sequences (ITSs) in Belostoma candidulum (2n = 12 + XY/XX; male/female), B. dentatum (2n = 26 + X1X2Y/X1X1X2X2), B. elegans (2n = 26 + X1X2Y/X1X1X2X2), B. elongatum (2n = 26 + X1X2Y/X1X1X2X2), B. micantulum (2n = 14 + XY/XX), and B. oxyurum (2n = 6 + XY/XX) by FISH with the (TTAGG)n probes. Hybridization signals confirmed the presence of TTAGG repeats in the telomeres of all species examined. The three species with reduced chromosome numbers showed additional hybridization signals in interstitial positions, indicating the occurrence of ITS. From the comparison of all species here analyzed, we observed inverse relationships between chromosome number and chromosome size, and between presence/absence of ITS and chromosome number. The ITS distribution between these closely related species supports the hypothesis that several telomere–telomere fusions of the chromosomes from an ancestral diploid chromosome number 2n = 26 + XY/XX played a major role in the karyotype evolution of Belostoma. Consequently, our study provide valuable features that can be used to understand the karyotype evolution, may contribute to a better understanding of taxonomic relationships, and also elucidate the high plasticity of nuclear genomes at the chromosomal level during the speciation processes. © 2017 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
author	Bressa, Maria Jose
author_facet	Bressa, Maria Jose
author_sort	Bressa, Maria Jose
title	Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
title_short	Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
title_full	Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
title_fullStr	Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
title_full_unstemmed	Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)
title_sort	chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (hemiptera, belostoma)
publishDate	2017
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_20457758_v7_n14_p5227_Chirino http://hdl.handle.net/20.500.12110/paper_20457758_v7_n14_p5227_Chirino
work_keys_str_mv	AT bressamariajose chromosomaldistributionofinterstitialtelomericsequencesassignsofevolutionthroughchromosomefusioninsixspeciesofthegiantwaterbugshemipterabelostoma
_version_	1840325525098201088

Chromosomal distribution of interstitial telomeric sequences as signs of evolution through chromosome fusion in six species of the giant water bugs (Hemiptera, Belostoma)

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