Partial inversion of gene order within a homologous segment on the X chromosome.

The locus for the erthyroid transcription factor, GATA1, has been positioned in the small interval between DXS255 and TIMP on the proximal short arm of the human X Chromosome (Chr) by use of a partial human cDNA clone and a well-characterized somatic cell hybrid panel. Analysis of selected recombinants from 108 Mus musculus x Mus spretus backcross progeny with the same clone confirmed that the homologous murine locus (Gf-1) lies between Otc and the centromere of the mouse X Chr. These data imply that a partial inversion of gene order has occurred within the conserved segment that represents Xp21.1-Xp11.23 in human (CYBB-GATA1) and the proximal 6 cM of the mouse X Chr (Gf-1-Timp). Furthermore, they indicate that the mouse mutant scurfy and the human genetic disorder Wiskott-Aldrich syndrome, which have been mapped to the same regions as GATA1/Gf-1 in both species, may indeed be homologous disorders.