Format: ORAL

Alicia Talavera1,2,Richard Hodel1,3, Elizabeth Zimmer1, Jun Wen1

1 Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington. DC, USA. 2 Departamento de Botánica y Fisiología Vegetal, Universidad de Málaga, Málaga, Spain. 3 Data Science Lab, Office of the Chief Information Officer, Smithsonian Institution, Washington, DC, USA.

Understanding the origin and distribution of species is a focal point of evolutionary biology. In North America, the current distribution and diversity of species have been substantially influenced by environmental changes during climatic oscillations, as well as historic and contemporary geographic barriers. Phylogeographic studies have revealed conflicting patterns among co-distributed taxa with distinct ecological requirements, suggesting dispersal ability and other life-history traits are crucial for shaping the diversity and distribution of the regions biota. However, a complete understanding of North Americas diversification dynamics is hampered by a limited number of comprehensive genome-scale phylogeographic studies that integrate phenotypic and environmental niche evidence. This is crucial for revealing intricate evolutionary mechanisms driving diversification, such as introgression/hybridization, ecological adaptation, and ecophenotypic plasticity, which might be overlooked through less integrative approaches. The grape genus Vitis L., especially subg. Vitis, serves as an ideal model for studying North Americas biogeography and phylogeography. Recent progress in genomics, phenomics, and specimen digitization offers an unprecedented opportunity to explore the convoluted evolutionary history of two challenging species complexes: Vitis aestivalis and Vitis cinerea. These taxa have extensively overlapping distributions throughout several biomes in North- and Mesoamerica. In this study, we sampled both species complexes across their distributional range. We employed several phylogenomic inference approaches to identify relationships within these complexes and hybridization events. Complementary population structure analyses were used to assess genetic diversity within and among sampling locations. Environmental variables were used to evaluate ecological differentiation as a driver of diversification, and phenotypic differences in leaf and stem characters were quantified to determine the extent of the influence of ecophenotypic plasticity. Our results support the recognition of several species in both the V. aestivalis and the V. cinerea complexes. Geographic isolation was important for species differentiation, and key phenotypic differences were detected among different ecological zones.