Phylogenomics Resolves the Relationships within Antennaria (Asteraceae, Gnaphalieae) and Yields New Insights into Its Morphological Character Evolution and Biogeography
Phylogenomics Resolves the Relationships within Antennaria (Asteraceae, Gnaphalieae) and Yields New Insights into Its Morphological Character Evolution and Biogeography
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DOI：
10.1600/036364420x15862837791221
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发表时间：
2020-05
影响因子：
1
通讯作者：
R. Thapa;R. J. Bayer;J. Mandel
中科院分区：
文献类型：
--
作者：
R. Thapa;R. J. Bayer;J. Mandel
摘要：天线草是一种主要分布于全北极地区的多年生雌雄异株草本植物，其主要多样性中心位于北美西部的落基山脉。该属包括33个已知的有性二倍体/四倍体物种和至少5个多倍体无性生殖复合体。我们使用一种新的靶标富集方法对31种有性繁殖的天线属物种进行了系统发育重建，该方法采用了设计用于跨Asteraceae的定制捕获探针。对数百个核位点的DNA序列数据进行串联和聚结分析，发现触角属是一个单系类群，但长期存在争议的线性触角属（Antennaria linearifolia）除外。触角虫进一步分为三个不同的主要谱系。12个重要形态性状的祖先状态重建分析，阐明了整个属的性状演化模式。祖先地理范围的估计和分子定年分析表明，包括温哥华省在内的落基山脉地区是天线属的起源中心，大约在5.8亿年前。随后，触角虫分别在大约3.2亿年前、2.4亿年前和1.6亿年前向北极和阿巴拉契亚省、加拿大省和欧亚大陆扩散。生物地理随机制图表明，51.4%的生物地理事件是基于区域内物种形成的。其余48.6%的分散事件分为2种类型：1)范围扩展分散（突变型，37%）和2)创始/跳跃分散（枝生型，11.6%）。我们的研究结果为未来天线属的进化研究提供了一个框架，包括物种形成、多倍体起源和无精子性。
Abstract Antennaria are dioecious perennial herbs distributed mainly in the Holarctic Region, with their major center of diversity in the Rocky Mountains of Western North America. The genus comprises 33 known sexual diploid/tetraploid species and at least five polyploid agamic complexes which mostly reproduce by forming asexual seeds. We performed a phylogenetic reconstruction of the 31 sexually-reproducing Antennaria species using a novel target enrichment method that employs custom capture probes designed to work across Asteraceae. Both concatenated and coalescent-based analyses of DNA sequence data from hundreds of nuclear loci recovered Antennaria as a monophyletic group except for the long-disputed species, Antennaria linearifolia, which was recovered outside of the genus. Antennaria was further resolved into three distinct, major lineages. Analysis of ancestral state reconstruction of 12 taxonomically important morphological characters elucidated patterns of character evolution throughout the genus. Estimations of ancestral geographic ranges and molecular dating analyses demonstrated the Rocky Mountain region, including the Vancouverian Province, as the center of origin for the genus Antennaria, around 5.8 MYA. Subsequent dispersals of Antennaria into the Arctic and Appalachian provinces, Canadian provinces, and Eurasia took place roughly 3.2 MYA, 2.4 MYA, and 1.6 MYA, respectively. Biogeographical stochastic mapping indicated that 51.4% of biogeographical events were based on within-area speciation. The remaining 48.6% of the events were divided into two types of dispersals: 1) range expansion dispersals (anagenic, 37%), and 2) founder/jump dispersals (cladogenic, 11.6%). Our results provide a framework for future evolutionary studies of Antennaria, including speciation, origin(s) of polyploidy, and agamospermy in the genus.