Fig. 6. Tetraploid aggregation chimeras composed of Elf5^-/- epiblast are developmentally normal. (A) PCR genotyping of the tail tips of chimeric embryos reveals the presence of four embryos, indicated by arrows, composed solely of Elf5^-/- cells. Embryo 5 had died and was not genotyped. (B,C) Chimeric embryos (embryo 13 shown) containing only wild-type (or wild-type and Elf5^+/–) cells in embryonic and extraembryonic compartments (B) were morphologically indistinguishable from chimeric embryos (embryo 14 shown) containing only Elf5^-/- diploid embryonic cells (C).