Segments containing 2.5 Mbp of DNA in the distal parts of the short arms of the human X and Y chromosomes that share homologous genes. These segments pair during meiosis, and obligatory crossing over takes place, so that genes in this region segregate like autosomal loci, rather than showing X or Y linkage. The gene MIC2 (q.v.) resides in this region. In the mouse, the steroid sulfatase gene (Sts) is pseudo-autosomal. The obligatory crossing over that occurs in the pseudoautosomal regions ensures that the X and Y chromosomes will segregate properly at the first meiotic division. See XG.
Subjects: Genetics and Genomics.