Schematic representation of samples and imprinted genes analysed. (A) Location of imprinted gene CpG islands (green box labelled GGI) and CpG dinucleotides covered by pyrosequencing analysis. Genes investigated were (clockwise from top left); SNRPN, MEST, PLAGL1, H19, PEG10 and IGF2R. (B)
in vivo embryos from non-stimulated, artificially inseminated heifers were isolated 7, 14, 17 and 25 Days post insemination and used for imprinted gene DNA methylation analysis. ICM = inner cell mass; TE = trophectoderm adjacent to embryonic disc; TP = trophectoderm peripheral; ExEmb = extraembryonic and Emb = embryonic.