Introgression and repeated co-option facilitated the recurrent emergence of C(4) photosynthesis among close relatives.
Introgression and repeated co-option facilitated the recurrent emergence of C(4) photosynthesis among close relatives.
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DOI：
10.1111/evo.13250
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发表时间：
2017-06
期刊：
影响因子：
--
通讯作者：
Christin PA
中科院分区：
文献类型：
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作者：
Dunning LT;Lundgren MR;Moreno-Villena JJ;Namaganda M;Edwards EJ;Nosil P;Osborne CP;Christin PA
新性状的起源通常使用物种树和将表型建模为同一性状的不同状态来研究，这种方法并不能总是区分多个起源和较少的起源，然后发生逆转。我们通过研究C4光合作用的起源来解决这个问题，这是一种对温暖和干燥条件的适应，在草中。我们将C4性状分解成其组成部分，并通过不同的解剖学修饰和不同基因组的使用显示了C4表型的两个独立起源。此外，酶适应的推断表明，两组之一包括两个过渡到一个完整的C4状态，从一个共同的祖先与中间表型，有一些C4解剖和生化成分。C4基因的分子年代测定证实了两个关键的C4组分在物种之间的渐渗，而所有其他组分的遗传与物种树相匹配。因此，C4成分之间的来源数量各不相同，这种情况不能仅从物种树的分析中推断出来。我们的研究结果强调了研究复杂性状的单个组成部分以重建新适应轨迹的力量。
The origins of novel traits are often studied using species trees and modeling phenotypes as different states of the same character, an approach that cannot always distinguish multiple origins from fewer origins followed by reversals. We address this issue by studying the origins of C4 photosynthesis, an adaptation to warm and dry conditions, in the grass Alloteropsis. We dissect the C4 trait into its components, and show two independent origins of the C4 phenotype via different anatomical modifications, and the use of distinct sets of genes. Further, inference of enzyme adaptation suggests that one of the two groups encompasses two transitions to a full C4 state from a common ancestor with an intermediate phenotype that had some C4 anatomical and biochemical components. Molecular dating of C4 genes confirms the introgression of two key C4 components between species, while the inheritance of all others matches the species tree. The number of origins consequently varies among C4 components, a scenario that could not have been inferred from analyses of the species tree alone. Our results highlight the power of studying individual components of complex traits to reconstruct trajectories toward novel adaptations.