The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene,but early diversifications of the temperate biome under global climate change and biome shift remain uncer...The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene,but early diversifications of the temperate biome under global climate change and biome shift remain uncertain.Moreover,it is becoming clear that hybridization/introgression is an important driving force of speciation in plant diversity.Here,we applied analyses from biogeography and phylogenetic networks to account for both introgression and incomplete lineage sorting based on genomic data from the New World Vitis,a charismatic component of the temperate North American flora with known and suspected gene flow among species.Biogeographic inference and fossil evidence suggest that the grapes were widely distributed from North America to Europe during the Paleocene to the Eocene,followed by widespread extinction and survival of relicts in the tropical New World.During the climate warming in the early Miocene,a Vitis ancestor migrated northward from the refugia with subsequent diversification in the North American region.We found strong evidence for widespread incongruence and reticulate evolution among nuclear genes within both recent and ancient lineages of the New World Vitis.Furthermore,the organellar genomes showed strong conflicts with the inferred species tree from the nuclear genomes.Our phylogenomic analyses provided an important assessment of the wide occurrence of reticulate introgression in the New World Vitis,which potentially represents one of the most important mechanisms for the diversification of Vitis species in temperate North America and even the entire temperate Northern Hemisphere.The scenario we report here may be a common model of temperate diversification of flowering plants adapted to the global climate cooling and fluctuation in the Neogene.展开更多
基金supported in part by grants from the National Natural Sciences Foundation of China(32060055,31570211)the United States National Science Foundation(DEB 0743474,0743499)+3 种基金the Smithsonian Endowment Grants Programthe Small Grants Programthe Global Genome Initiative of the National Museum of Natural Historythe Smithsonian Barcode Network。
文摘The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene,but early diversifications of the temperate biome under global climate change and biome shift remain uncertain.Moreover,it is becoming clear that hybridization/introgression is an important driving force of speciation in plant diversity.Here,we applied analyses from biogeography and phylogenetic networks to account for both introgression and incomplete lineage sorting based on genomic data from the New World Vitis,a charismatic component of the temperate North American flora with known and suspected gene flow among species.Biogeographic inference and fossil evidence suggest that the grapes were widely distributed from North America to Europe during the Paleocene to the Eocene,followed by widespread extinction and survival of relicts in the tropical New World.During the climate warming in the early Miocene,a Vitis ancestor migrated northward from the refugia with subsequent diversification in the North American region.We found strong evidence for widespread incongruence and reticulate evolution among nuclear genes within both recent and ancient lineages of the New World Vitis.Furthermore,the organellar genomes showed strong conflicts with the inferred species tree from the nuclear genomes.Our phylogenomic analyses provided an important assessment of the wide occurrence of reticulate introgression in the New World Vitis,which potentially represents one of the most important mechanisms for the diversification of Vitis species in temperate North America and even the entire temperate Northern Hemisphere.The scenario we report here may be a common model of temperate diversification of flowering plants adapted to the global climate cooling and fluctuation in the Neogene.