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ABSTRACT The application of high‐throughput sequencing to phylogenetic analyses is allowing authors to reconstruct the true evolutionary history of species. This work can illuminate specific mechanisms underlying divergence when combined with analyses of gene flow, recombination and selection. We conducted a phylogenomic analysis ofCatharus, a songbird genus with considerable potential for gene flow, variation in migratory behaviour and genomic resources. We documented discordance among trees constructed for mitochondrial, autosomal and sex (Z) chromosome partitions. Two trees were recovered on the Z. Both trees differed from the autosomes, one matched the mitochondria, and the other was unique to the Z. Gene flow with one species likely generated much of this discordance; substantial admixture betweenustulatusand the remaining species was documented and linked to at least two historic events. The tree unique to the Z likely reflects the true history ofCatharus; local genomic analyses recovered the same tree in autosomal regions with reduced admixture and recombination. Genes previously connected to migration were enriched in these regions suggesting transitions between migratory and non‐migratory states helped generate divergence. Migratory (vs. nonmigratory)Catharusformed a monophyletic clade in a subset of genomic regions. Gene flow was elevated in some of these regions suggesting adaptive introgression may have occurred, but the dominant pattern was of balancing selection maintaining ancestral polymorphisms important for olfaction and perhaps, by extension, adaptation to temperate climates. This work illuminates the evolutionary history of an important model in speciation and demonstrates how differential resistance to gene flow can affect local genomic patterns.
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This content will become publicly available on December 1, 2026
Phylogenetic comparative analysis of functional morphology sheds light on the evolution of seasonal migration in nightingale-thrushes (Turdidae: Catharus)
Not AvailableThis study investigates the evolution of locomotory morphology and migratory behavior in nightingale-thrushes (genus Catharus), a clade of songbirds with diverse migratory strategies. With large datasets of molecular and morphometric characters, we resolve phylogenetic relationships, identify and model migration-related morphological characters, and estimate ancestral states of those characters to infer evolutionary transitions in the migratory phenotype. While acknowledging that unknown factors (e.g., differential extinction) may confound interpretation, our results suggest that (1) migratory behavior and its functional morphology are fundamentally linked; (2) short-distance or elevational migration (not long-distance) was the ancestral state of Catharus; (3) short-distance migration was the evolutionary precursor of long-distance migration; and (4) the short-distance migrant, Hermit Thrush (C. guttatus), may be in relative phenotypic (ecological) stasis. This potentially explains the ecological incumbency of C. guttatus in temperate North America during winter, and offers a new framework for interpreting the evolutionary sequence that produced long-distance migration in this model system.
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- Award ID(s):
- 2203228
- PAR ID:
- 10638689
- Publisher / Repository:
- Nature Portfolio
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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