Epigenetic

Methylation, the transfer of a methyl group (―CH3) to an organic compound. Methyl groups may be transferred through addition reactions or substitution reactions; in either case, the methyl group takes the place of a hydrogen atom on the compound. ... Biological methylation occurs in various ways. Presently, the exact role of methylation in gene expression is unknown, but it appears that proper DNA methylation is essential for cell differentiation and embryonic development. Moreover, in some cases, methylation has observed to play a role in mediating gene expression DNA methylation regulates gene expression by recruiting proteins involved in gene repression or by inhibiting the binding of transcription factor(s) to DNA. During development, the pattern of DNA methylation in the genome changes as a result of a dynamic process involving both de novo DNA methylation and demethylation. Evidence suggests that DNA methylation of the gene body is associated with a higher level of gene expres...

  Epigenetic regulation of gene expression is a frequent process that occurs during somatic cell development, as well as in response to environmental signals and stresses, and epigenetic inheritance is the transmission of these modulations to children. These changes must be heritable in the progeny of either cells or organisms, according to the basic definition of epigenetics. The phrase also refers to the alterations themselves, which are functionally meaningful changes to the genome that do not involve a nucleotide sequence change. Parental imprinting is another type of epigenetic inheritance that was found in animals about ten years ago. Certain autosomal genes have atypical inheritance patterns in parental imprinting. The mouse Igf2 gene, for example, is only expressed in a mouse if it was inherited from the mouse's father.

  In ageing and cancer, genetic and epigenetic changes in DNA lead to altered gene expression. Epigenetic alterations such as DNA methylation, histone modifications, microRNAs, and nucleosome remodelling all influence gene expression in human malignancies. All human malignancies have epigenetic changes, which are now recognised to work together with genetic abnormalities to cause the cancer phenotype. DNA methylation, histone modifiers and readers, chromatin remodelers, microRNAs, and other chromatin components are all involved in these modifications. Epigenetics is the study of how your behaviour and environment can influence how your genes function. Epigenetic alterations, unlike genetic changes, are reversible and do not alter your DNA sequence; nevertheless, they can alter how your body interprets a DNA sequence. Thus, epigenetic abnormalities in DNA repair may play a role in the high frequency of mutations found in cancer genomes, as well as their carcinogenic develop...

  DNA methylation alterations are also known to occur as people get older and are linked to aging-related disorders. As a result, it appeared plausible that stress's effects on aging-related disease were mediated in part by alterations in DNA methylation generated by glucocorticoid receptor activation. Changes in DNA methylation are significantly linked to ageing. In a wide range of animals ranging in complexity from yeast to humans, DNA methylation and epigenetic changes have been directly related to lifespan. Stress can cause changes in DNA methylation, which can affect gene expression and so contribute to disease phenotypes. Stress in childhood, such as maltreatment and stress-related diseases, has long-term impacts on methylation that can endure into adulthood. In humans, age has become the primary risk factor for various diseases, since many genes appear to show altered expression during the aging. altered expression in response to internal and external environmental...