Reference mapping and whole-genome alignment yield comparable phylogenomic inferences

By Westbury, DucheneOct 21, 2026

Score████░░░░░░4.3

Caveats

Preprint; not yet peer reviewed.

VerdictWorth a reader's time today.

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Abstract

Reference-genome choice can introduce mapping bias when sequencing data are analysed against a heterospecific genome, but it remains unclear how strongly this bias affects species-level phylogenomic inference. We tested this across Ursidae using nine species spanning approximately 20 million years of divergence, including the extinct giant short-faced bear (Arctodus simus). We independently mapped the same sequencing datasets to four reference genomes spanning a broad range of evolutionary distances and compared these with two assembly-based whole-genome-alignment approaches. We developed PhyloSlide to analyse all treatments consistently, offering a streamlined pipeline for sliding-window phylogenomics. Using this approach, we found that mapping reference choice strongly affected sequence recovery, with missing data generally increasing with evolutionary distance. Nonetheless, all six treatments recovered an identical species-tree topology and highly similar gene and site concordance factors. Relative divergence-time estimates were also largely consistent between approaches. Together, these findings demonstrate that mapping sequencing reads from multiple species to a shared reference genome can yield phylogenomic inferences comparable to whole-genome alignment, despite substantial reference-dependent sequence loss across millions of years of evolutionary divergence.

M. V. Westbury, D. A. Duchene

The editor's rubric

Heuristic review

Leverage3 / 5: A method or resource many groups across the field will adopt within a year.; 24% of this desk’s rubric
Magnitude2 / 5: Solid incremental gain on a meaningful problem.; 16% of this desk’s rubric
Evidence3 / 5: Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.; 20% of this desk’s rubric
Novelty2 / 5: A new combination of known ideas.; 20% of this desk’s rubric
Trajectory3 / 5: A clear path to scale.; 10% of this desk’s rubric
Stakes3 / 5: Meaningful benefit to many people within a few years.; 10% of this desk’s rubric

Dimension	Level	Weight	What that level means
Leverage	███░░ 3	24%	A method or resource many groups across the field will adopt within a year.
Magnitude	██░░░ 2	16%	Solid incremental gain on a meaningful problem.
Evidence	███░░ 3	20%	Solid: multiple benchmarks or cohorts, ablations, fair baselines, released code or data.
Novelty	██░░░ 2	20%	A new combination of known ideas.
Trajectory	███░░ 3	10%	A clear path to scale.
Stakes	███░░ 3	10%	Meaningful benefit to many people within a few years.

Editor’s rationale

Heuristic triage from title and abstract text only, not a reading of the paper. Cues found: breadth (wide range, many tasks); verification (multiple benchmarks, independent replication); stakes (global scale, prevention or cure).

How the score was computed

rank-2026-10-18

Score████░░░░░░4.3

Score = 10 × (75% × adjusted merit / 10 + 15% × attention + 10% × freshness)

Desks place stronger verdicts first, then use this score to order work within the same verdict.

Merit: 5.3 / 10; Weighted rubric, evidence-gated.
Adjusted merit: 4.5 / 10; Shrunk toward the desk prior by editor confidence (42%).
Attention: 0%; Citations, upvotes, points, mentions.
Freshness: 88%; Half-life decay since publication.

No attention signals recorded yet.

The record

Reviewed by heuristic-v7 on Oct 22, 2026, 05:48 UTC. Paper type: empirical.
Categories: evolutionary biology
BRIEF, No.8 in the Biology edition of October 22, 2026.