Mapping the testis determinants by an analysis of Y-specific sequences in males with apparent XX and XO karyotypes and females with XY karyotypes

A number of patients with paradoxical sex chrcmoeome complements (so-called XY females, XX and XO males) have been investigated with a series of 19 Yp and 1 Yq DNA probes to establish which region of the Y is essential far male sexual differentiation. Of the 23 XX males, 18 possessed one or more Yp probe sequences with only 5 lacking such sequences. Of 9 XY females exanined, only one showed evidence of a deletion in Yp occurring either as a result of X-Y interchange or interstitial deletion. This suggests that the majority of XY fanales are not cannonly deleted for those Y sequences which are found to be transferred to the X in XX males. The ENA of two XO males both contained different portions of the Y. Prom a canparison of the patterns of Yp sequences In these patients, it has been possible to elaborate a model of Yp in terms of the order of probe sequences and to suggest a location far the testis determining region in distal Yp. PfTROEUCTION