410 
Monitoring- Stem 
Fig. 5: Blastocysts retain epigenetic 
Blastocysts can be derived from the fertilized egg or by nuclear 
transfer. After implantation development of the embryo strictly 
depends on the donor nucleus: Blastocysts derived from a fertilized 
egg will develop with high efficiency to normal animals; blastocysts 
derived by NT from an ES ceil donor will develop with high eMciency 
to abnormal animals; blastocysts derived by HT from a fibroblast or 
cumulus ceil donor will develop with low efficiency to abnormal 
animals; blastocysts derived by NT from B or T donor cells will not 
develop to newborns by direct transfer into the womb (only by a 2 
step procedure, compare (Hochedlinger and Jaenisch, 2002a). 
Nuclear Donor 
Fertilbetf Zraote 
Divtidpmint 
T# fiiwliem 
{ffidtiicy; 
Normal 
iSotll 
fibroblast 
E,T€tll, 
itlifOH 
Hlfh 
low 
ytfff low 
} Abnormal 
(latse 
orrspHng 
Syndrome) 
Sisstdtjrsi 
PRE -PUBLICATION VERSION 
