Fig. 4 Comparative genomic analysis of P. tomentosa with other plants. ( a ) Shared gene families among P. tomentosa and three other poplars. The numbers indicate the number of genes (within each category). ( b ) Interspecific divergence inSalicaceae species, and intraspecific divergence inPopulus species inferred by synonymous substitution rates (Ks ) between collinear orthologous and paralogous pairs respectively. ( c ) Common genome duplication events (Ks= 0.25, ~60 Mya) in Salix andPopulus species (Dai et al., 2014; J. Ma et al., 2019), P. tomentosaspeciation (Ks = 0.005, ~3.93 Mya) and divergence events of other poplars as revealed through Ks analysis. (d ) Inferred phylogenetic tree across 10 plant species using r8s (Sanderson, 2003). WGD events ofSalicaceae species are placed. ( e ) Synteny between theP. tomentosa genome (the horizontal axis) and P. trichocarpa genome (the vertical axis). The P. tomentosachromosomes were inferred to be syntenous with P. trichocarpachromosomes based on orthologous genes from OrthoMCL analysis.
Figure 5