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Genomic divergence of Stellera chamaejasme through local selection on the Qinghai-Tibet Plateau and adjacent regions
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  • Hongyin Hu,
  • Yongzhi Yang,
  • Ao Li,
  • Zeyu Zheng,
  • Jin Zhang,
  • Jianquan Liu
Hongyin Hu
Lanzhou University

Corresponding Author:[email protected]

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Yongzhi Yang
Lanzhou University
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Ao Li
Lanzhou University
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Zeyu Zheng
Lanzhou University
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Jin Zhang
Lanzhou University
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Jianquan Liu
Sichuan University
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Understanding how populations diverge and new species arise is a central question in evolutionary biology. ‘Allopatric’ divergence through geographic isolation is considered to be the commonest mechanism generating species biodiversity in mountainous ecosystems. However, the underlying genomic dynamics, especially genomic islands of elevated divergence and genes that are highly diverged as a result of lineage-specific selection, remain poorly understood. Stellera chamaejasme is widely distributed on the Qinghai-Tibet Plateau and in adjacent regions, making it a good model with which to explore genomic divergence in mountainous ecosystems. We assembled a high-quality, chromosome-level genome for this species and re-sequenced the genomes of 24 populations across its distributional range. Our population genomic analyses recovered four distinct genetic lineages corresponding to geographic distributions with contrasting environments. However, we revealed that continuous gene flow occurred during the diversification of these four lineages and inter-lineage hybrids, and plastome introgressions were frequently found in regions of contact. The elevated genomic divergences were highly heterogeneous across the genome. The formation of such genomic islands showed neither correlation with rate of gene flow nor relationship to time of divergence. The lineage-specific positively selected genes potentially involved in local adaptation were found both within and outside genomic islands. Our results suggest that genomic divergence in S. chamaejasme is likely to have been triggered and further maintained by local selection in addition to geographic isolation.
30 Mar 2022Submitted to Molecular Ecology
31 Mar 2022Submission Checks Completed
31 Mar 2022Assigned to Editor
08 Apr 2022Reviewer(s) Assigned
19 May 2022Review(s) Completed, Editorial Evaluation Pending
24 May 2022Editorial Decision: Revise Minor
21 Jun 2022Review(s) Completed, Editorial Evaluation Pending
21 Jun 20221st Revision Received
21 Jun 2022Reviewer(s) Assigned
14 Jul 2022Editorial Decision: Revise Minor
16 Jul 2022Review(s) Completed, Editorial Evaluation Pending
16 Jul 20222nd Revision Received
18 Jul 2022Editorial Decision: Accept