Pluripotency of Homozygous‐Diploid Mouse Embryos in Chimeras

Pluripotency of mouse uniparental cells (complete homozygous-diploid gynogenetic) produced by embryo manipulation was examined in aggregation chimeras with normally fertilized embryos. A male pronucleus was removed from fertilized eggs by micromanipulation and eggs were diploidized with cytochalasin B. Uniparental cells that developed to 4-cell or more advanced stages were aggregated with normally fertilized 8-cell embryos and transferred to the pseudopregnant female uteri to develop to term. Among the pups, 1 female and 3 males were identified as overt chimeras by their coat color and pigmentation of the retina. Using electophoretic analysis of the isozymes, the contribution of uniparental cells in these chimeras was confirmed by findings in the major organs such as liver, brain, small intestine, kidney, spleen, heart and testis. The female chimera produced offspring derived from oocytes of uniparental origin. Our experiments verified the pluripotency of microsurgically produced mouse uniparental cells.