Figure 2.
Schematic representation of the evolution of the PAR2 on the human X chromosome. SYBL1 lies at a telomeric position on the original therian X. HSPRY3 and CXYorf1 were added first followed by an inversion to make HSPRY3 proximal to SYBL1. IL9R was added later, and then a second inversion occurred to make CXYorf1 telomeric.
