---
_id: '14604'
abstract:
- lang: eng
  text: Sex chromosomes have evolved independently multiple times, but why some are
    conserved for more than 100 million years whereas others turnover rapidly remains
    an open question. Here, we examine the homology of sex chromosomes across nine
    orders of insects, plus the outgroup springtails. We find that the X chromosome
    is likely homologous across insects and springtails; the only exception is in
    the Lepidoptera, which has lost the X and now has a ZZ/ZW sex-chromosome system.
    These results suggest the ancestral insect X chromosome has persisted for more
    than 450 million years—the oldest known sex chromosome to date. Further, we propose
    that the shrinking of gene content the dipteran X chromosome has allowed for a
    burst of sex-chromosome turnover that is absent from other speciose insect orders.
acknowledgement: All computational analyses were performed on the server at Institute
  of Science and Technology Austria. We thank Marwan Elkrewi and Vincent Bett for
  analytical advice, and Tanja Schwander and Vincent Merel for useful discussions.
  We also thank Matthew Hahn for comments on an earlier version of the manuscript.
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Melissa A
  full_name: Toups, Melissa A
  id: 4E099E4E-F248-11E8-B48F-1D18A9856A87
  last_name: Toups
  orcid: 0000-0002-9752-7380
- first_name: Beatriz
  full_name: Vicoso, Beatriz
  id: 49E1C5C6-F248-11E8-B48F-1D18A9856A87
  last_name: Vicoso
  orcid: 0000-0002-4579-8306
citation:
  ama: Toups MA, Vicoso B. The X chromosome of insects likely predates the origin
    of class Insecta. <i>Evolution</i>. 2023;77(11):2504-2511. doi:<a href="https://doi.org/10.1093/evolut/qpad169">10.1093/evolut/qpad169</a>
  apa: Toups, M. A., &#38; Vicoso, B. (2023). The X chromosome of insects likely predates
    the origin of class Insecta. <i>Evolution</i>. Oxford University Press. <a href="https://doi.org/10.1093/evolut/qpad169">https://doi.org/10.1093/evolut/qpad169</a>
  chicago: Toups, Melissa A, and Beatriz Vicoso. “The X Chromosome of Insects Likely
    Predates the Origin of Class Insecta.” <i>Evolution</i>. Oxford University Press,
    2023. <a href="https://doi.org/10.1093/evolut/qpad169">https://doi.org/10.1093/evolut/qpad169</a>.
  ieee: M. A. Toups and B. Vicoso, “The X chromosome of insects likely predates the
    origin of class Insecta,” <i>Evolution</i>, vol. 77, no. 11. Oxford University
    Press, pp. 2504–2511, 2023.
  ista: Toups MA, Vicoso B. 2023. The X chromosome of insects likely predates the
    origin of class Insecta. Evolution. 77(11), 2504–2511.
  mla: Toups, Melissa A., and Beatriz Vicoso. “The X Chromosome of Insects Likely
    Predates the Origin of Class Insecta.” <i>Evolution</i>, vol. 77, no. 11, Oxford
    University Press, 2023, pp. 2504–11, doi:<a href="https://doi.org/10.1093/evolut/qpad169">10.1093/evolut/qpad169</a>.
  short: M.A. Toups, B. Vicoso, Evolution 77 (2023) 2504–2511.
date_created: 2023-11-26T23:00:54Z
date_published: 2023-11-02T00:00:00Z
date_updated: 2025-09-09T13:32:06Z
day: '02'
ddc:
- '570'
department:
- _id: BeVi
doi: 10.1093/evolut/qpad169
external_id:
  isi:
  - '001170341900014'
  pmid:
  - '37738212'
file:
- access_level: open_access
  checksum: b66dc10edae92d38918d534e64dda77c
  content_type: application/pdf
  creator: dernst
  date_created: 2023-11-28T08:12:15Z
  date_updated: 2023-11-28T08:12:15Z
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  file_name: 2023_Evolution_Toups.pdf
  file_size: 1399102
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file_date_updated: 2023-11-28T08:12:15Z
has_accepted_license: '1'
intvolume: '        77'
isi: 1
issue: '11'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '11'
oa: 1
oa_version: Published Version
page: 2504-2511
pmid: 1
publication: Evolution
publication_identifier:
  eissn:
  - 1558-5646
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
related_material:
  link:
  - relation: software
    url: https://git.ista.ac.at/bvicoso/veryoldx
  record:
  - id: '14616'
    relation: research_data
    status: public
  - id: '14617'
    relation: research_data
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scopus_import: '1'
status: public
title: The X chromosome of insects likely predates the origin of class Insecta
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 77
year: '2023'
...