Drift drives the evolution of chromosome number II: The impact of range size on genome evolution in Carnivora

Summary

Ingested 2026-04-21. 2 findings extracted and verified.

Findings worth citing

Finding 1 — In Carnivora, lineages with small range sizes show higher rates of both chromosome fusions and fissions than lineages with large range sizes, with 95% credible intervals entirely above zero.

We found a ΔR fusion of 0.101 (CI 0.062 to 0.141) and a ΔR fission of 0.163 (CI 0.116 to 0.207) — p. 527

Why this is citable: This is the paper’s central quantitative result linking effective population size (via range size) to karyotype evolution rates, directly supporting drift-based models of chromosome number evolution.

Counter / limitation: Range size is an indirect proxy for effective population size and was discretized at the median; simulated neutral traits produced false positive rates of 22–33%, so the inference depends on the magnitude of the observed effect exceeding typical false positives.

Topics: karyotype_evolution_overview, selection_and_drift, chromosome_number_evolution

Finding 2 — Analysis of neutral simulated binary traits on the Carnivora phylogeny yielded false positive rates of 22% for fusion and 33% for fission under the chromePlus framework.

We found that 22% of neutral traits were associated with elevated rates of fusion, and 33% were associated with elevated rates of fissions. — p. 528

Why this is citable: This quantifies a methodological weakness (false-positive susceptibility) for trait-dependent chromosome-number-evolution models, informing future users about the reliability of chromePlus-style inferences.

Counter / limitation: Only 7% of neutral simulations reached ΔR magnitudes as extreme as the empirical data, so the false positive rate in isolation overstates concern when effect sizes are considered; also specific to the Carnivora tree topology.

Topics: chromosome_number_evolution, comparative_methods

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