Pseudoautosomal regions
pseudoautosomal regions
At either end of the X and Y chromosomes are homologous regions known as the pseudoautosomal regions (PARs). These two regions pair regularly at male meiosis and undergo recombination. PAR1 is at the tip of the short 'p' arms (Xp22 and Yp11) and PAR2 is at the tip of the long 'q' arms (Xq28 and Yq12). There has been a report of a third pseudoautosomal region (PAR3), but this remains uncorroborated (PMID: 23708688).