Mapping the limits of the human pseudoautosomal region and a candidate sequence for the male-determining gene.

The human Y chromosome is composed of two different parts: a pseudoautosomal region shared with the X chromosome which is responsible for sex chromosome pairing and a Y-specific part that encodes the sex determining gene. Previously we have shown that the pseudoautosomal gene MIC2 only rarely recombines between the sex chromosomes and, based on the elevated recombination rates in the pseudoautosomal region, we predicted that this gene would lie close to the Y-specific region. In this report we describe a test of this prediction using long-range restriction mapping techniques. We conclude that MIC2 is less than 200 kilobases (kb) away from Y-specific sequences. During these experiments we have identified an HTF island in a position consistent with the proposed location of the human sex determining gene.