Chimeric primates: embryonic stem cells need not apply.
In this issue, Tachibana et al. report the generation of the first chimeras from a nonhuman primate, the rhesus monkey. Unlike mice, rhesus chimeras fail to form when embryonic stem cells are injected into blastocysts. Instead, chimera formation is achieved by aggregation of several four-cell embryos.
California Institute for Regenerative Medicine, 210 King Street, San Francisco, CA 94107, USA. atrounson@cirm.ca.gov
Alan
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Trounson
Uta
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Grieshammer