Fig. 5

Schematic representation of gene flow and pod morphology in Glycyrrhiza species. The schematic diagram summarizes the inferred evolutionary history and gene flow between G. glabra (Gg) and G. uralensis (Gu) based on the results of this study. Approximately 930,000 years ago (930 K), Gg and Gu diverged from a common ancestor¹². Around 100,000 years ago (100 K), during a period of increased effective population size in Glycyrrhiza species as suggested by PSMC analysis, extensive gene flow occurred between the two species. This gene flow resulted in the formation of the Ggu group, with Gg as the maternal parent and Gu as the paternal parent, and the Gug group, with Gu and Gg as the maternal and paternal parents, respectively. The diagram also shows the pod morphology of the current Gg, Ggu, Gug, and Gu groups, illustrating their phenotypic differences.