アンドロサケ属植物の最も完全な系統関係を再構築(Researchers Reconstruct Most Complete Phylogeny of Androsace)

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2026-08-31 中国科学院(CAS)

中国科学院西双版納熱帯植物園(XTBG)の研究チームは、100種を超えるトチナイソウ属(Androsace)と近縁種について、葉緑体ゲノムと核DNAを解析し、これまでで最も包括的な系統樹を構築しました。その結果、Douglasia、Vitaliana、Pomatosaceなど従来は別属とされていた植物群がAndrosace属内に含まれることを確認し、広義のAndrosaceとして統合すべきことを示しました。分子時計と化石記録を組み合わせた解析から、現生Androsace類の共通祖先は約3300万年前の漸新世初期、現在の青海・チベット高原、ヒマラヤ、横断山脈を含む地域に生息していたと推定。高原の隆起や寒冷化に伴う高山環境の形成を背景に、ユーラシア西方や北米へ繰り返し分散したと考えられます。系統群は4つの主要クレードに分かれ、地質変動、気候変動、形態進化が山岳植物の多様化を促したことも示されました。

アンドロサケ属植物の最も完全な系統関係を再構築(Researchers Reconstruct Most Complete Phylogeny of Androsace)
Species richness, sample distribution, and representative species of Androsace (Image by XTBG)

<関連情報>

北半球におけるサクラソウ科(Androsace sl .)のマクロ進化ダイナミクス Macroevolutionary dynamics of Androsace s.l. (Primulaceae) across the Northern Hemisphere

Chuan Peng, Chihchieh Yu, Wenna Ding, Liqiong Chen, Qiuyue Zhang, Yaoke Li, Florian C. Boucher, Sébastien Lavergne, Yaowu Xing
Journal of Systematics and Evolution  Published: 13 August 2026
DOI:https://doi.org/10.1111/jse.70099

Abstract

Mountain regions of the Northern Hemisphere harbor exceptional biodiversity, yet the processes underlying species diversification and migration among these regions remain poorly understood. This study investigates the macroevolutionary dynamics of Androsace s.l., a genus widely distributed across temperate regions of the Northern Hemisphere, with notable diversity in the Alps and the Hengduan–Himalaya regions. Although previous phylogenetic studies have advanced understanding of the evolutionary history of Androsace, its biogeographic origins and diversification history have remained unresolved due to limited species sampling and low statistical support. Here, we revisited the inter- and infrageneric taxonomic controversies. Using chloroplast genome (cpDNA) and nuclear ribosomal ITS (nrDNA) sequences from 101 species representing four related genera and seven infrageneric sections, we reconstructed the most comprehensively sampled phylogeny of Androsace to date and established a spatiotemporal framework for its biogeographic and diversification history. Phylogenetic analyses based on cpDNA revealed four well-supported clades corresponding to distinct ecological, geographic, and morphological traits. A similar four-clade structure was recovered in the ITS phylogeny, albeit with lower statistical support. Divergence time estimation and biogeographic analyses traced the origin of Androsace s.l. to the Pan-Tibetan Highlands in the early Oligocene (~33 Ma), identifying this region as the source for other mountain systems. The genus underwent asynchronous diversification across different mountain systems and clades, driven by distinct tectonic events, environmental changes, and trait innovations. These results provide a spatiotemporal framework for understanding the evolution of alpine plants in the Northern Hemisphere.

細胞遺伝子工学
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