PCR detection of distal Yp sequences in an XX true hermaphrodite.

An XX true hermaphrodite was examined for the presence of Y-specific sequences using Southern-blotting and polymerase chain reaction (PCR) techniques. Of 25 loci examined, only two, the proximal border of the pseudoautosomal region (PABY) and the sex determining region of the Y chromosome (SRY), were detected. A crossing over event in paternal meiosis, proximal to the SRY locus but distal to the zinc finger protein (ZFY) locus, presumably transferred to two loci to the X chromosome.