File:Pseudoautosomal regions and SRY gene in human Y chromosome.gif

English: Pseudoautosomal regions and SRY gene in human Y chromosome. The pseudoautosomal regions get their name because any genes located within them (so far only 9 have been found) are inherited just like any autosomal genes. Males have two copies of these genes: one in the pseudoautosomal region of their Y, the other in the corresponding portion of their X chromosome. So males can inherit an allele originally present on the X chromosome of their father and females can inherit an allele originally present on the Y chromosome of their father.

Although 95% of the Y chromosome lies between the pseudoautosomal regions, only 27 different functional genes have been found here. Over half of this region is genetically-barren heterochromatin. Of the 27 genes found in the euchromatin, some encode proteins used by all cells. The others encode proteins that appear to function only in the testes. A key player in this latter group is SRY.