The study investigates the prevalence of paleopolyploidy in 14 model plant species by analyzing the age distributions of duplicate genes. Using EST contigs, pairs of paralogous genes were identified, and the level of synonymous nucleotide substitution was used to estimate their relative ages. For nine of the investigated species, the age distributions of duplicated genes show peaks corresponding to short evolutionary periods during which large numbers of duplicated genes accumulated, indicating ancient large-scale duplications. However, the unusual age profile of tandem gene duplications in Arabidopsis suggests that other factors, such as variation in the rate of gene deletion, must also be considered. The findings highlight the widespread occurrence of polyploidy in angiosperms and its impact on plant evolution and systematics.The study investigates the prevalence of paleopolyploidy in 14 model plant species by analyzing the age distributions of duplicate genes. Using EST contigs, pairs of paralogous genes were identified, and the level of synonymous nucleotide substitution was used to estimate their relative ages. For nine of the investigated species, the age distributions of duplicated genes show peaks corresponding to short evolutionary periods during which large numbers of duplicated genes accumulated, indicating ancient large-scale duplications. However, the unusual age profile of tandem gene duplications in Arabidopsis suggests that other factors, such as variation in the rate of gene deletion, must also be considered. The findings highlight the widespread occurrence of polyploidy in angiosperms and its impact on plant evolution and systematics.