Data from: Sympatric parallel diversification of major oak clades in the Americas and the origins of Mexican species diversity

Oaks (Quercus, Fagaceae) are the dominant tree genus of North America in species number and biomass, and Mexico is a global center of oak diversity. Understanding the origins of oak diversity is key to understanding biodiversity of northern temperate forests.
A phylogenetic study of biogeography, niche evolution and diversification patterns in Quercus was performed using 300 samples, 146 species. Next-generation sequencing data were generated using the restriction-site associated DNA (RAD-seq) method. A time-calibrated maximum likelihood phylogeny was inferred and analyzed with bioclimatic, soils, and leaf habit data to reconstruct the biogeographic and evolutionary history of the American oaks.
Our highly resolved phylogeny demonstrates sympatric parallel diversification in climatic niche, leaf habit, and diversification rates. The two major American oak clades arose in what is now the boreal zone and radiated, in parallel, from eastern North America into Mexico and Central America.
Oaks adapted rapidly to niche transitions. The Mexican oaks are particularly numerous, not because Mexico is a center of origin, but because of high rates of lineage diversification associated with high rates of evolution along moisture gradients and between the evergreen and deciduous leaf habits. Sympatric parallel diversification in the oaks has shaped the diversity of North American forests.

栎属（Quercus，Fagaceae）是北美物种数量与生物量均占据优势的树木类群，而墨西哥则是全球栎属物种多样性的核心分布中心。阐明栎属多样性的起源，是理解北温带北部森林生物多样性的关键。
本研究针对栎属的生物地理学、生态位演化及物种分化模式开展系统发育分析，共纳入300份样本、146个物种。研究采用限制性酶切位点相关DNA测序（RAD-seq）技术生成二代测序数据，进而构建了时间校准的最大似然系统发育树，并结合生物气候、土壤及叶片习性数据进行分析，以重建北美栎属的生物地理与演化历史。
本研究获得的高分辨率系统发育树表明，栎属在气候生态位、叶片习性及物种分化速率维度均存在同域平行分化现象。北美两大主要栎属演化支起源于现今的寒温带区域，并以平行辐射的方式从北美东部扩散至墨西哥与中美洲地区。
栎属物种可快速适应生态位转变。墨西哥栎属物种数量尤为丰富，并非因其为栎属的起源中心，而是由于其演化支分化速率较高，且在湿度梯度间以及常绿与落叶叶片习性之间的演化速率更快。栎属的同域平行分化塑造了北美森林的物种多样性格局。