Capturing Totipotent Stem Cells.

Minority subpopulations within embryonic stem cell cultures display an expanded developmental potential similar to that of early embryo blastomeres or the early inner cell mass. The ability to isolate and culture totipotent cells capable of giving rise to the entire conceptus would enhance our capacity to study early embryo development, and might enable more efficient generation of chimeric animals for research and organ production for transplantation. Here we review the biological and molecular characterization of cultured cells with developmental potential similar to totipotent blastomeres, and assess recent progress toward the capture and stabilization of the totipotent state in vitro.