The evolution of grass spikelets

Monocotyledons comprise around 56,000 flowering plants, contained within various divergent lineages.  The true grasses, Poaceae are the  most economically important monocotyledons (including grains, sugar canes and bamboo), and have a morphologically distinct form of inflorescence, 1-40 flowers which are collected into evolutionarily novel  structures known as grass spikelets.

In EvoDevo last week, new research published by Christensen and Malcomber uses a combination of Bayesian  phylogenetics, expression analyses, molecular evolutionary analyses, and Maximum parsimony and Maximum likelihood character reconstruction methods to investigate the evolutionary history of developmental genes associated with spikelet formation. They explore both the timing of the evolutionary event which produced paralogs between lineages, and the supporting evidence for how genetic alterations lead to subfunctionalization and/or neofunctionalization in the two lineages studied.

Gene expression analysis shows a complex pattern of evolution associated with spikelet development, which Christensen and Malcomber discuss in detail. How this translates to a morphological context is yet to be determined, and several areas for further research are suggested by the authors in order to expand on their results.   

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