Lineage-specific patterns of chromosome evolution are the rule not the exception in Polyneoptera insects
Summary
Ingested 2026-04-21. 2 findings extracted and verified.
Findings worth citing
Finding 1 — Fusions are the dominant route for transitions from XO to XY sex chromosome systems in Polyneoptera, with 94% (16/17) of genera containing both XO and XY species showing lower mean autosome number in XY species.
We find strong support for fusions as a source of transitions from XO to XY SCSs. Of the 17 genera with both XO and XY species, 94% (16/17) show a lower mean number of autosomes in XY species — p. 3
Why this is citable: This is a central empirical claim of the paper that quantifies the contribution of sex chromosome–autosome fusions to SCS turnover, grounding broader hypotheses about sexually antagonistic selection driving sex chromosome evolution.
Counter / limitation: The genus-level comparison uses only genera that contain multiple SCSs and does not jointly model chromosome number and SCS on a phylogeny, so the inference is correlational and the authors themselves note patterns differ at order-level.
Topics: sex_chromosome_evolution, karyotype_evolution_overview
Finding 2 — Rates of polyploidy are significantly higher in asexually reproducing Phasmatodea lineages than in sexually reproducing lineages, while fusion and fission rates do not differ between reproductive modes.
we find that rates of polyploidy are significantly higher in asexually reproducing lineages than in sexually reproducing lineages — p. 4
Why this is citable: Provides a testable quantitative claim linking reproductive mode to a specific mode of karyotype change, useful for citations on constraints to polyploidy and the evolutionary consequences of asexuality.
Counter / limitation: Based on only 13 parthenogenetic species within a single order (Phasmatodea) and on ancestral reconstructions of reproductive mode, so generality to other clades and robustness to sampling is limited.
Topics: karyotype_evolution_overview, chromosome_number_evolution
Read the paper
doi.org/10.1098/rspb.2020.1388
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