ABSTRACT
Analysis of gene expression has also been undertaken to examine the progress of epigenetic reprogramming in the germ line (Figure 6.1b). In primordial germ cells, monoallelic expression of imprinted genes would be expected prior to the erasure of methylation imprints. At E9.5, monoallelic expression of four imprinted genes was detected19. As development progressed, biallelic expression of Snrpn (E10.5) and of H19 and Igf2 (E11.5) was detected. Analysis of embryos generated by somatic cell nuclear transfer using nuclei from primordial germ cells isolated from mice at various gestational ages has also pointed to demethylation of the genome in primordial germ cells between E10.5 and E12.522,23.
