Does polyploidy facilitate long-distance dispersal?
Does polyploidy facilitate long-distance dispersal?
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DOI：
10.1093/aob/mcu047
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发表时间：
2014-06
期刊：
影响因子：
4.2
通讯作者：
H. Peter Linder;Nigel P. Barker
中科院分区：
文献类型：
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作者：
H. Peter Linder;Nigel P. Barker
背景和目的植物谱系能够到达所有大陆的能力对它们的进化成功有很大的贡献。禾本科是最成功的被子植物科之一，其中大多数高等分类群（族，亚科）具有全球分布。由于相对于主要被子植物辐射的海洋盆地的年龄较大，这只能通过长距离扩散（LDD）来实现，但具有成功LDD的谱系的属性仍然不清楚。多倍体物种在入侵植物区系和先前冰川化的北极地区中过度代表，并且通常比二倍体具有更广泛的生态耐受性;因此多倍体是成功LDD的候选属性。方法在全球分布的禾草亚科Danthonioideae中探索多倍体与LDD之间的联系。一个几乎完全采样和良好解决的种水平的danthonioids的遗传学，可用的细胞学信息进行了组装。在进化枝的细胞学进化推断使用最大似然法（ML），在ChromEvol中实现。在进化枝的地理进化重建使用ML和贝叶斯方法。关键结果证明了倍性水平的大量增加。晚中新世-上新世的多倍体循环与LDD有关，在两个案例中（澳大利亚的Rytidosperma和美国的Danthonia）导致了二次多倍体。虽然证明了在多倍体谱系中比在二倍体谱系中更可能成功LDD，但并未证明多倍体化事件与LDD之间的联系。结论多倍体比二倍体在LDD上更成功，并且禾本科植物中频繁的多倍体可能促进了该科植物在大陆之间的广泛传播，从而有助于其进化成功。
BACKGROUND AND AIMS The ability of plant lineages to reach all continents contributes substantially to their evolutionary success. This is exemplified by the Poaceae, one of the most successful angiosperm families, in which most higher taxa (tribes, subfamilies) have global distributions. Due to the old age of the ocean basins relative to the major angiosperm radiations, this is only possible by means of long-distance dispersal (LDD), yet the attributes of lineages with successful LDD remain obscure. Polyploid species are over-represented in invasive floras and in the previously glaciated Arctic regions, and often have wider ecological tolerances than diploids; thus polyploidy is a candidate attribute of successful LDD. METHODS The link between polyploidy and LDD was explored in the globally distributed grass subfamily Danthonioideae. An almost completely sampled and well-resolved species-level phylogeny of the danthonioids was used, and the available cytological information was assembled. The cytological evolution in the clade was inferred using maximum likelihood (ML) as implemented in ChromEvol. The biogeographical evolution in the clade was reconstructed using ML and Bayesian approaches. KEY RESULTS Numerous increases in ploidy level are demonstrated. A Late Miocene-Pliocene cycle of polyploidy is associated with LDD, and in two cases (the Australian Rytidosperma and the American Danthonia) led to secondary polyploidy. While it is demonstrated that successful LDD is more likely in polyploid than in diploid lineages, a link between polyploidization events and LDD is not demonstrated. CONCLUSIONS The results suggest that polyploids are more successful at LDD than diploids, and that the frequent polyploidy in the grasses might have facilitated the extensive dispersal among continents in the family, thus contributing to their evolutionary success.