Fig. 2: Karyotype evolution and evolutionary relationship of Populus, Salix and the related genera from the common ancestral karyotype.
From: Ancient allopolyploidy and specific subgenomic evolution drove the radiation of poplars and willows
The evolutionary relationships were constructed based on the shared polyploidy events and chromosome fusions with the shortest steps. The inferred ancestral karyotype contains 11 protochromosomes, marked with different colors. Leaf nodes show the modern karyotypes of species, and chromosomal changes leading to the formation of these modern karyotypes, including RTA, EEJ and NCF, are marked on the ancestral nodes of the phylogenetic tree. Among them, the ancestor of Clade II experienced a RTA, resulting in the karyotype of ancestor A, and subsequently hybridized with ancestor B of another branch (which is now extinct), leading to an allopolyploidization event, which is indicated by a red star. The Dianyuea-specific WGD event (autopolyploidization) is marked by a purple star. Chromosomes from ancestor B are distinguished by white asterisks in the center of the chromosomes. The dashed lines indicate unresolved relationships for karyotypes of existing species. Source data are provided as a Source Data file.
