Repeated shifts out of tropical climates preceded by whole genome duplication
Climate can constrain the distribution of biological diversity. However, at certain points in history flowering plants have overcome climatic constraints on their distribution, enabling them to thrive and diversify in virtually every terrestrial climate. Shifts into new climates may be associated with the diverse evolutionary phenomena that have been recorded in flowering plants such as whole genome duplication, genomic conflict, and life history shifts. Climatic shifts may also have facilitated recent increases in flowering plant diversification rates.We investigate climatic shifts in the flowering plant order Ericales, which consists of around 14,000 species distributed in diverse climates and exhibiting varied life histories. We estimate a new phylogenetic tree for this order from transcriptomic data that incorporates 147 Ericales species, and two species level phylogenetic trees from 63 plastid loci and Angiosperms353 nuclear loci that incorporate 5,000 and 2,800 species respectively. We analyse these phylogenetic trees alongside a bioclimatic dataset to identify major climatic shifts and determine their links with whole genome duplication, genomic conflict, life history shifts, and diversification.We show a statistically significant link between major climatic shifts into colder, seasonal, or arid climates, and whole genome duplication and life history shifts. We also show that early branches within Ericales are extremely short, and that they are associated with high levels of genomic conflict and whole genome duplication which may have facilitated adaptation to diverse climates in descendant lineages. However, we establish no link between climatic shifts and rates of diversification.Overall, we characterise adaptation to diverse climates, and its associated molecular evolutionary phenomena in a globally distributed flowering plant clade.