Gene structure of P. abies WOX genes. Exons are thick and black, introns are thin lines. The conserved homeobox region is striped diagonally. The repeat regions in PaWUS are striped vertically. The gene structure of PaWOX13 is only putative. Due to long introns exon 1 and 3 are derived from cDNA sequence data only. End of known intron sequences are marked with lines.