Despite their low developmental competence, the
quality of lymphocyte-derived HMC blastocysts was comparable
to that of blastocysts produced from skin fibroblasts,
at least in terms of TCN and the level of apoptosis.
Another indication of their normalcy was their epigenetic
status, which was comparable to that of IVF embryos in
terms of the global level of H3K9ac and H3K27me3. This
finding is important because aberrant reprogramming is
considered to be responsible for abnormality of cloned
embryos and their low offspring rate [23,24]. Methylation
status of histone H3 at the three positions lysines 4 (H3K4),
9 (H3K9), and 27 (H3K27) is markedly reduced in quiescent
lymphocytes, which have a correspondingly greater
developmental potential after SCNT [25].
Compared to their IVF counterparts, SCNT embryos
exhibit aberrant gene expression due to incomplete
epigenetic reprogramming [26], which results in adverse
effects on their development [27]. DNA methylation is
considered as one of the most important epigenetic events
due to its ability to reversibly repress the genes. We found
the opposite pattern in relative expression level of DNMT1,