The Genomic Architecture of Local Adaptation in Two Connected Populations of Three-Spined Stickleback
Notice bibliographique
Résumé
Abstract Populations often adapt to their local environments despite the homogenizing effects of gene flow, but the genomic mechanisms enabling this process remain unclear. Theory predicts that adaptive divergence under high connectivity is favored when beneficial alleles cluster in regions of reduced recombination, a pattern that can be reinforced by structural variants (SVs). We investigated this in three-spined sticklebacks (Gasterosteus aculeatus) from the St. Lawrence Estuary, where distinct freshwater and marine ecotypes meet and interbreed along a short ecological gradient. Using long- and short-read whole-genome sequencing, we mapped fine-scale recombination landscapes, catalogued SVs, and examined their relationship with adaptive genomic regions. Recombination landscapes differed between populations, with population-specific shifts in recombination rate estimated by an LD-based method. Putatively adaptive regions were not confined to low-recombination regions, yet SVs (inversions, insertions, and deletions) frequently coincided with local recombination suppression and elevated differentiation, suggesting they may contribute to local adaptation. Differentiated regions also overlapped disproportionately with previously-identified regions involved in repeated local adaptation across the species range, which tended to be strongly enriched on chromosomes IV, VII and XXI. These repeated regions were associated with lower recombination rates, suggesting that recombination suppression may contribute to their reuse across populations. As found in stickleback populations from other regions, the St. Lawrence populations exhibit elements suggestive of concentrated architectures clustered in a few genomic regions, along with relatively diffuse patterns of highly differentiated regions distributed genome-wide, across a wide range of recombination rates. These results highlight the intertwined roles of recombination variation and structural variation in shaping evolutionary trajectories in connected populations. Article Summary This study investigates how recombination and structural variants shape local adaptation in the three-spined stickleback ( Gasterosteus aculeatus ). Using long- and short-read genome sequencing, the authors compared recombination landscapes and structural variants between marine and freshwater populations from the St. Lawrence Estuary. They found population-specific changes in recombination rate and frequent overlap between structural variants, reduced recombination, and genomic regions showing high differentiation. These findings suggest that variation in recombination and structural variants jointly influence how adaptation proceeds in connected populations, providing new insights into the genomic mechanisms that maintain diversity despite ongoing gene flow.
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Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
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