[Regional localization of the genes for human IDHs, MDHs PGK, alphaGAL, G6PD by interspecific hybridization (author's transl)].

22 independent man-hamster (HGPRT-) hybrids using male human cells with balanced reciprocal translocation t(X;2)(p22;q32) were analysed for human genes localized on chromosome 2 (IDHs, MDHs), on chromosome X (PGK, alphaGAL, G6PD) and for the different chromosomes in relation with the balanced reciprocal translocation (chr.2, chr.2q-, chr.Xp+). The following results were obtained: The chromosomes 2 and 2q- are absent in the 22 hybrids. In 9 hybrids, the absence of MDHs in spite of the presence of the chromosome Xp+ indicates that the gene for MDHs is not localized on this chromosome (or that the gene for MDHs is not on the segment 2q32--2qter translocated on X). In 14hybrids, the three markers of X (PGK, alphaGAL, G6PD) and IDHs are expressed in the presence of the chromosome Xp+. This result indicates that the genes for these markers are on Xp+ or that the genes PGK, alphaGAL, G6PD are on X without the Xp22--Xter segment, translocated on the chr.2, and that the gene for IDHs is on the 2q32--2qter segment translocated on X. In 8 hybrids, in the absence of the intack chromosome Xp+, the higher percentage of the presence of G6PD (7 hybrids) and the lower percentage of the presence of IDHs (3 hybrids) are explained by the fact that these hybrids selected in HAT medium had to retain a segment of Xp+ bearing the human gene HGPRT. G6PD appeared very close to HGPRT and IDHs very distant from HGPRT. The study of the different correlations between the presence and the absence of these four markers on Xp+ in the different hybrids indicates the following order on the chromosome Xp+ from p to q: IDHs -- PGK --alphaGAL -- G6PD.