Chromosomal locations of
. 114 of 118 Hsf and Hsp genes are mapped to 19 chromosomes. The schematic diagram of Populus genome-wide chromosome organization arisen from the whole genome duplication event was adapted from Tuskan et al.  and Chai et al. . Homologous blocks derived from segmental duplication are indicated using the same colors. Small circles connected by colored line indicate corresponding sister gene pairs.