Evolutionary history of Fagaceae

The flowering plant family Fagaceae (ca. 1000 species; e.g., beeches, oaks, and chestnuts) plays a major ecological role in several broadly distributed ecosystems of the Northern Hemisphere.

Paul Manos and Sang-Hun Oh are conducting a thorough evolutionary investigation of this remarkable diversification of woody species. Ideally, the study of the pattern and process of species diversification or speciation requires a robust estimate of phylogeny, accurate knowledge of taxonomic diversity, and a rich fossil record. In Fagaceae, these criteria are nearly in place, making it a premier group for the research.

Research completed to date establishes a robust platform to produce a genealogy of Fagaceae using several DNA regions, specifically alternative low-copy nuclear genes across 75 species. The resulting phylogeny will be used to address long-standing classical questions regarding the evolution of reproductive traits, as well as to independently assess traditionally described genera. A range of methods designed to statistically evaluate hypotheses of convergence will be used to gain further insight into the complexity of reproductive trait evolution. A second goal requires the use of fossils to calibrate the evolutionary history of the family. Within this chronicle of evolution, hypotheses of key innovation or critical factors linked to increases in the speciation rate, will be tested using established methods that test for shifts in species richness. Measures of phylogenetic diversity or the amount of DNA variation also will be compared among groups to test for significant differences that may correlate with shifts in the rate of diversification.

This research links several aspects of macroevolutionary analysis to produce an explicit account of this ecologically significant diversification. While the family Fagaceae is well-studied, the synthesis proposed here has not been attempted before, and its implications reach beyond systematic biology and into emerging investigations of the causes of diversification and its consequences to molecular and phylogenetic diversity.

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