Fig. 2

Structure of the human Y chromosome with male specific region (MSY) and the PAR1 and PAR2 regions labeled. The pseudo autosomal regions (PAR1 and PAR2) are located at two terminals of the Y chromosome. The short arm of the human Y chromosome (Yp) contains 14 genes, which are all directly or indirectly-related to cell cycle/mitosis/meiosis/proliferation. The long arm of the human Y chromosome (Yq) is composed of euchromatin encoding for azoospermia factors (AZFa, AZFb and AZFc) and with a gap between AZFa and AZFb (Gap a/b). There is also a genetically inactive heterochromatin region distributed between AZFc and PAR2