Chromosome distribution and duplications of PHB genes in Arabidopsis. Diagram of five chromosomes of Arabidopsis was depicted, 17 PHB family genes were distributed on the chromosomes. Only segmental duplicated regions containing PHB genes are shown. Blue lines connected genes from recent polyploidy duplication blocks (Black boxes), black lines connected genes from old segmental duplication blocks (Gray boxes). At5g25259 and At5g25269 are clustered as tandem repeat.