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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Out of patterns, the euchromatic B chromosome of the grasshopper Abracris flavolineata is not enriched in high-copy repeats

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Author(s):
Milani, Diogo [1] ; Ruiz-Ruano, Francisco J. [2, 3] ; Camacho, Juan Pedro M. [4] ; Cabral-de-Mello, Diogo C. [1]
Total Authors: 4
Affiliation:
[1] Univ Estadual Paulista, Inst Biociencias IB, Dept Biol Geral & Aplicada, UNESP, Rio Claro, SP - Brazil
[2] Uppsala Univ, Evolutionary Biol Ctr, Dept Organismal Biol Systemat Biol, Uppsala - Sweden
[3] Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich, Norfolk - England
[4] UGR Univ Granada, Fac Ciencias, Dept Genet, Granada - Spain
Total Affiliations: 4
Document type: Journal article
Source: HEREDITY; v. 127, n. 5 SEP 2021.
Web of Science Citations: 0
Abstract

In addition to the normal set of standard (A) chromosomes, some eukaryote species harbor supernumerary (B) chromosomes. In most cases, B chromosomes show differential condensation with respect to A chromosomes and display dark C-bands of heterochromatin, and some of them are highly enriched in repetitive DNA. Here we perform a comprehensive NGS (next-generation sequencing) analysis of the repeatome in the grasshopper Abracris flavolineata aimed at uncovering the molecular composition and origin of its B chromosome. Our results have revealed that this B chromosome shows a DNA repeat content highly similar to the DNA repeat content observed for euchromatic (non-C-banded) regions of A chromosomes. Moreover, this B chromosome shows little enrichment for high-copy repeats, with only a few elements showing overabundance in B-carrying individuals compared to the 0B individuals. Consequently, the few satellite DNAs (satDNAs) mapping on the B chromosome were mostly restricted to its centromeric and telomeric regions, and they displayed much smaller bands than those observed on the A chromosomes. Our data support the intraspecific origin of the B chromosome from the longest autosome by misdivision, isochromosome formation, and additional restructuring, with accumulation of specific repeats in one or both B chromosome arms, yielding a submetacentric B. Finally, the absence of B-specific satDNAs, which are frequent in other species, along with its euchromatic nature, suggest that this B chromosome arose recently and might still be starting a heterochromatinization process. On this basis, it could be a good model to investigate the initial steps of B chromosome evolution. (AU)

FAPESP's process: 14/11763-8 - Contributions to understanding of structure and evolution of sex chromosome systems using as models grashopper and cricket species
Grantee:Diogo Cavalcanti Cabral de Mello
Support Opportunities: Regular Research Grants
FAPESP's process: 15/16661-1 - Sex and B chromosome enigmas: model systems for the study of chromosome and genome evolution
Grantee:César Martins
Support Opportunities: Research Projects - Thematic Grants