Epigenetic Changes Passed on from Generation to Generation
It is important to understand the basics of epigenetic changes, which occur in DNA. There are many molecular mechanisms of epigenetic reprogramming, which include DNA methylation, as well as processes leading to a change in chromatin state, non-coding RNA. Important and relatively recently discovered factors of epigenetic reprogramming are the spatial organization of the nucleus, X-chromosomal inactivation, gene imprinting, the mosaic effect of position, paramutation, and mono-allelic expression. It is these molecular changes that are able to maintain in different tissues and organs those features of gene expression that give them all the necessary properties and distinguish some tissues and organs from others.
DNA methylation is a modification of a DNA molecule without changing its nucleotide sequence, which can be considered as part of the epigenetic component of the genome. In humans, DNA methylation involves the attachment of a methyl group to cytosine using specific enzymes. Thus, the chromatin structure of a certain chromosome locus changes, which leads to inhibition of gene expression without structural disruption. As is known, DNA methylation controls a large number of genetic mechanisms in the cell – replication, transcription, DNA repair, recombination, gene transposition, and is also a mechanism for the differentiation of cells and tissues, discrimination and repression of genes. DNA methylation also performs a protective function – it inhibits the expression of exogenous viral and other harmful DNA sequences. However, it can be stated that certain strong epigenetic changes can be passed on, but epigenetics mostly bounded by one’s ontological development.