{
  "id": 10487995,
  "title": "Isoform inflation and annotation heterogeneity can confound Kunitz-repertoire comparisons in blood-feeding animals: a gene-level reappraisal",
  "url": "https://urgent.news/2026/09/28/isoform-inflation-and-annotation-heterogeneity-can-confound-kunitz",
  "topic": "finance",
  "section": "Finance & Markets",
  "published": "2026-09-28T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.22.753331v1?rss=1"
  },
  "original_language": "en",
  "account": "Hematophagy, or blood-feeding, has evolved independently multiple times throughout Metazoa. Families of anticoagulant proteins, such as the Kunitz/BPTI domain, are often associated with these blood-feeders, with the leech often cited as an exception. To examine this association further, researchers applied a gene-level protocol to eight metazoan lineages. They discovered that while blood-feeders had a median of 18 Kunitz-repertoire genes compared to a median of 39 in non-blood-feeders, this did not represent a consistent, universal elevation in gene-level Kunitz-repertoire size. The researchers also found that protein-entry counts can inflate gene-level Kunitz counts by up to 4.6 times. Additionally, neither protein-entry counts nor proteome-wide isoform density correlated with diet, making protein-entry comparisons an unreliable basis for repertoire claims. The researchers also found that 12 independent blood-feeding origins could be counted using deterministic bookkeeping, although this number may be lower if the ancestral lamprey is considered a parasitic species with two losses. A screen of annotated public genomes yielded only one candidate blood/non-blood pair, the bedbug. Under the pre-registered simulation scenario, only a cross-origin heterogeneity endpoint was attainable within a realistic origin ceiling, and only under strong heterogeneity among origins. The researchers caution about isoform/annotation bias in cross-phylum comparisons and emphasize the need for a gene-level, annotation-aware re-analysis. They also highlight the limitations of current data in supporting claims about cross-phylum associations.",
  "summary": "Hematophagy has arisen independently many times across Metazoa, and recurrent anticoagulant protein families in blood-feeders are often read as convergent recruitment - the Kunitz/BPTI domain a paradigm case, with the leech an oft-cited low-Kunitz exception. We re-examine this at the gene level and ask whether a confirmatory cross-phylum test of this blood-feeding/anticoagulant association is…",
  "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."
}