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arXiv · 1409.4978

Phenotypic landscape inference reveals multiple evolutionary paths to C$_4$ photosynthesis

Ben P. Williams·Iain G. Johnston·Sarah Covshoff·Julian M. Hibberd
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Abstract

C$_4$ photosynthesis has independently evolved from the ancestral C$_3$ pathway in at least 60 plant lineages, but, as with other complex traits, how it evolved is unclear. Here we show that the polyphyletic appearance of C$_4$ photosynthesis is associated with diverse and flexible evolutionary paths that group into four major trajectories. We conducted a meta-analysis of 18 lineages containing species that use C$_3$, C$_4$, or intermediate C$_3$-C$_4$ forms of photosynthesis to parameterise a 16-dimensional phenotypic landscape. We then developed and experimentally verified a novel Bayesian approach based on a hidden Markov model that predicts how the C$_4$ phenotype evolved. The alternative evolutionary histories underlying the appearance of C$_4$ photosynthesis were determined by ancestral lineage and initial phenotypic alterations unrelated to photosynthesis. We conclude that the order of C$_4$ trait acquisition is flexible and driven by non-photosynthetic drivers. This flexibility will have facilitated the convergent evolution of this complex trait.

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Ben P. Williams, Iain G. Johnston, Sarah Covshoff, Julian M. Hibberd. 2014-09-17. Phenotypic landscape inference reveals multiple evolutionary paths to C$_4$ photosynthesis. https://doi.org/10.7554/elife.00961

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