Most Compositae (Asteraceae) are descendants of a paleohexaploid and all share a paleotetraploid ancestor with the Calyceraceae
Most Compositae (Asteraceae) are descendants of a paleohexaploid and all share a paleotetraploid ancestor with the Calyceraceae
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DOI：
10.3732/ajb.1600113
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发表时间：
2016-07-01
影响因子：
3
通讯作者：
Rieseberg, Loren H.
中科院分区：
文献类型：
--
作者：
Barker, Michael S.;Li, Zheng;Rieseberg, Loren H.
研究的前提：像许多其他开花植物一样，菊科（菊科）的成员有一个多倍体祖先。先前的分析发现了该家族早期进化史中古代重复或可能三重的证据。我们试图更好地把这个古多倍体在的acromegeny和评估其nature.METHODS：我们测序新的转录组为Barnadesia，谱系姐妹所有其他菊科，和四个代表密切相关的家庭。使用最近开发的算法，MAPS，我们分析了核基因家族的同源性证据的paleopolyploidy.KEY结果：我们发现，以前公认的菊科paleopolyploidy也是在祖先的萼科。我们的基因组分析发现的证据，连续第二轮的基因组复制所有采样的菊科除Barnadesia.CONCLUSIONS：我们的新样本与新工具的分析提供了一个修订后的观点，在菊科的古多倍体。结合高密度莴苣属连锁图的结果，我们的研究结果表明，菊科和萼科有一个共同的paleotetraploid祖先和大多数菊科的后代paleohexaploid。虽然古六倍体先前已被确定，这是第一个例子，其中古四倍体和古六倍体谱系已经存活了数千万年。复杂的多倍性在菊科和萼科的祖先代表了一个独特的机会，研究长期的进化命运和不同倍性水平的后果。
PREMISE OF THE STUDY: Like many other flowering plants, members of the Compositae (Asteraceae) have a polyploid ancestry. Previous analyses found evidence for an ancient duplication or possibly triplication in the early evolutionary history of the family. We sought to better place this paleopolyploidy in the phylogeny and assess its nature.METHODS: We sequenced new transcriptomes for Barnadesia, the lineage sister to all other Compositae, and four representatives of closely related families. Using a recently developed algorithm, MAPS, we analyzed nuclear gene family phylogenies for evidence of paleopolyploidy.KEY RESULTS: We found that the previously recognized Compositae paleopolyploidy is also in the ancestry of the Calyceraceae. Our phylogenomic analyses uncovered evidence for a successive second round of genome duplication among all sampled Compositae except Barnadesia.CONCLUSIONS: Our analyses of new samples with new tools provide a revised view of paleopolyploidy in the Compositae. Together with results from a high density Lactuca linkage map, our results suggest that the Compositae and Calyceraceae have a common paleotetraploid ancestor and that most Compositae are descendants of a paleohexaploid. Although paleohexaploids have been previously identified, this is the first example where the paleotetraploid and paleohexaploid lineages have survived over tens of millions of years. The complex polyploidy in the ancestry of the Compositae and Calyceraceae represents a unique opportunity to study the long-term evolutionary fates and consequences of different ploidal levels.