We are always amused and mesmerized by seeing twins around us and talking about how nature has driven these events. The scientific fact underlying is Identical twins arise from a single fertilized egg. Prevailing hypothesis is that it occurs random in families but now there is more light shed on this theory. It’s purely predetermined Epigenetic signature programming. Sounds very interesting right! Every event in this process is a mystery. Majority of its programming events are associated with stable DNA methylation signature. It has something to do with lifelong signature.
Jenny et al published in nature that this particular signature is located and enriched near telomeres and centromeres, Polycomb-repressed regions and heterochromatin, genes involved in cell-adhesion, WNT signalling, cell fate and putative human metastable epialleles.
DNA Methylation is majorly involved in embryonic development. The methylome of pre implantation embryo undergoes multiple folds of DNA demethylation and followed by de novo methylation. These regions and methylation of CpG islands contribute to silencing of embryonic genes and imprinted genes. Monozygotic (MZ) signature comprises of 834 CpG sites along with strong genetic influences by common variants and gene-gene interactions. Along with this Cadherin gene, WNT/PCP signalling pathway is particularly responsible in hypermethylation. Interesting fact is that hypomethylation was enriched near telomeres and hypermethylation was enriched near centromeres in different patterns. Transcription factor motifs and pathways contribute and drive cell fate specification, early genome programming, early embryonic development, and cell adhesion.
Deep sequencing technologies in NGS can help to get a better understanding of methylomes, interactomes and related epigenetic regions at full resolution and also could provide a wider and better picture of epigenetics and its importance in Genome Programming.