Multiple Continental Radiations and Correlates of Diversification in Lupinus (Leguminosae): Testing for Key Innovation with Incomplete Taxon Sampling
Multiple Continental Radiations and Correlates of Diversification in Lupinus (Leguminosae): Testing for Key Innovation with Incomplete Taxon Sampling
复制标题
DOI：
10.1093/sysbio/syr126
复制
发表时间：
2012-05-01
影响因子：
6.5
通讯作者：
Hughes, Colin E.
中科院分区：
文献类型：
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作者：
Drummond, Christopher S.;Eastwood, Ruth J.;Hughes, Colin E.
复制辐射提供了强大的比较系统，以解决有关机会和创新之间在推动多样化时期的相互作用以及限制其后续进展的因素的问题。然而，这种系统很少在洲际规模上被记录在案。在这里，我们评估了羽扇豆属(豆科)的多重辐射假说，它在植物中表现出一些已知的最高的净多样化比率。鉴于不完全的分类单元采样、背景灭绝和谱系特有的多样性比率的差异可能会混淆关于分支发生的时间和机制的宏观进化推断，我们使用贝叶斯松弛时钟系统发育分析以及水母和Bisse出生-死亡可能性模型来评估羽扇豆属的谱系积累的进化模式。我们确定了三个显著的转变，即相对于该属的背景水平，净多样化比率(R)增加(r=0.18-0.48个谱系/MYR)。第一次漂移发生在北美西部山地，约4.6 Ma(r=0.48-1.76)，第二次漂移约2.7 Ma(r=0.89-3.33)，与墨西哥高地和安第斯山脉分布的姐妹分支的范围扩大和多样化有关。我们还在南美东部低海拔草原和坎波卢佩斯特支系的底部恢复了第三次独立位移的证据，约6.5 Ma(r=0.36-1.33)。贝叶斯祖先状态重建和相关多样性的Bisse似然分析表明，物种形成率的增加与多年生生活史的衍生进化和山地生态系统的入侵密切相关。尽管我们目前缺乏“复制适应性辐射”的确凿证据，在不同支系的物种之间存在收敛的形态和生态轨迹，但这些结果与迭代作为适应性关键创新发挥作用的假设是一致的，为新大陆大部分地区的高海拔地区提供了一种范围扩大和快速分歧的机制。
Replicate radiations provide powerful comparative systems to address questions about the interplay between opportunity and innovation in driving episodes of diversification and the factors limiting their subsequent progression. However, such systems have been rarely documented at intercontinental scales. Here, we evaluate the hypothesis of multiple radiations in the genus Lupinus (Leguminosae), which exhibits some of the highest known rates of net diversification in plants. Given that incomplete taxon sampling, background extinction, and lineage-specific variation in diversification rates can confound macroevolutionary inferences regarding the timing and mechanisms of cladogenesis, we used Bayesian relaxed clock phylogenetic analyses as well as MEDUSA and BiSSE birth-death likelihood models of diversification, to evaluate the evolutionary patterns of lineage accumulation in Lupinus. We identified 3 significant shifts to increased rates of net diversification (r) relative to background levels in the genus (r = 0.18-0.48 lineages/myr). The primary shift occurred approximately 4.6 Ma (r = 0.48-1.76) in the montane regions of western North America, followed by a secondary shift approximately 2.7 Ma (r = 0.89-3.33) associated with range expansion and diversification of allopatrically distributed sister clades in the Mexican highlands and Andes. We also recovered evidence for a third independent shift approximately 6.5 Ma at the base of a lower elevation eastern South American grassland and campo rupestre clade (r = 0.36-1.33). Bayesian ancestral state reconstructions and BiSSE likelihood analyses of correlated diversification indicated that increased rates of speciation are strongly associated with the derived evolution of perennial life history and invasion of montane ecosystems. Although we currently lack hard evidence for "replicate adaptive radiations" in the sense of convergent morphological and ecological trajectories among species in different clades, these results are consistent with the hypothesis that iteroparity functioned as an adaptive key innovation, providing a mechanism for range expansion and rapid divergence in upper elevation regions across much of the New World.