Phylogenetic Analysis of Fagaceae: A Study of the Pattern and Process of Woody Plant Diversification

Duke University, Durham NC

Investigators

Abstract

The flowering plant family Fagaceae (ca. 1000 species, including the beeches, oaks, and chestnuts) plays a major ecological role in several broadly distributed ecosystems of the Northern Hemisphere. Duke University researchers Paul Manos and Sang-Hun Oh propose to conduct 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 species relationships, accurate knowledge of species numbers, and a rich fossil record. In the oak family (Fagaceae), these conditions are nearly in place, making it a premier group for the research proposed. 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 genealogy will be used to address long-standing classical questions regarding the evolution of reproductive structures and traits, and independently to assess traditionally described genera. 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. The proposed research aims to link 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 genealogical diversity. The proposed research will integrate training at several levels. Dr. Sang-Hun Oh will train and benefit from a range of evolutionary activities present at Duke University. A graduate student will receive training in the methods proposed, and the research team will include two undergraduate students to be recruited through a Duke summer program funded through the NSF REU-Sites program. Proposed outreach activities include the development of a website dedicated to Fagaceae research at Duke, which will form the basis for an expanded contribution to the Tree of Life Project.