{
  "id": 5681085,
  "title": "Reconstruction of the gastropod ancestral karyotype reveals lineage-specific chromosomal evolution and adaptations during habitat transitions",
  "url": "https://urgent.news/2026/09/04/reconstruction-of-the-gastropod-ancestral-karyotype-reveals-lineage",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-04T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.02.748897v1?rss=1"
  },
  "original_language": "en",
  "account": "The study of gastropod chromosomal evolution reveals a diverse array of adaptations to various habitats, challenging the notion of a uniform genomic mechanism. By assembling chromosome-level genomes for five gastropod representatives from four distinct subclasses, researchers have reconstructed the ancestral gastropod karyotype, consisting of 20 linkage groups (GLGs) and individual karyotypes for each subclass. Integrating macro-synteny and phylogenomic analyses across all six subclasses, the study shows that different lineages have adopted unique chromosomal strategies to colonize novel environments. Freshwater caenogastropods feature extensive end-to-end fusions, terrestrial heterobranchs exhibit whole genome duplications, freshwater neritimorphs undergo lineage-specific fissions and fusions, and deep sea hydrothermal vent vetigastropods demonstrate widespread chromosomal restructuring. In contrast, deep sea hydrothermal vent neomphaliones and caenogastropods maintain a remarkably conserved ancestral karyotype. The study also reveals that rearrangement breakpoints preferentially occur within topologically associating domains (TADs) rather than at boundaries, preserving higher-order chromatin architecture. Functionally, convergent enrichment of the mucin type O glycan biosynthesis pathway is observed in both freshwater and hydrothermal vent lineages, accompanied by lineage-specific modifications. Enhanced immune modulation is noted in freshwater lineages, while reinforced physicochemical shielding is observed in deep sea lineages, reflecting divergent adaptive applications of this pathway. These findings highlight the extraordinary genomic flexibility that underpins the remarkable gastropod diversity observed today, demonstrating that habitat transitions are facilitated by a diverse repertoire of lineage-specific chromosomal strategies, rather than a single genomic mechanism.",
  "summary": "Gastropoda is the most diverse class of molluscs, with spectacular adaptive radiations across shallow to deep marine, freshwater, and terrestrial environments, yet the role of chromosomal restructuring behind these habitat transitions remain largely unexplored. This is in part due to most chromosomal genomes available are in the subclasses Caenogastropoda and Heterobranchia, with few…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}