FIG. 1.

Scheme to generate mice from two fathers using iPS cells. Somatic cells from Father #1 are reprogrammed to generate iPS cells that are screened for the spontaneous loss of the Y chromosome to isolate XO clones. These XY-derived XO iPS cells are injected into blastocysts to generate female chimeras. The female chimeras serve as surrogates to differentiate oocytes from the XY-derived XO iPS cells and carry the progeny to term (dashed line). Genetically, the progeny from the female chimera are sons and daughters of Father #1 and Father #2 (horizontal line). Blue boxes, male phenotype; pink boxes, female phenotype; blue letters, alleles derived from Fathers #1 and #2.