Kochar Kaur K,Allahbadia G and Singh M
Basically epigenetic mechanisms control development and regulate gene expression in various types of cells of the organism, each carrying similar DNA sequence. In simple language, the nucleotides of DNA are letters of the complicated text and these epigenetic labels or marks are the spaces, punctuations, sentences, paragraphs and styles which give meaning to this complicated text. Here we have tried to discuss the epigenetic markers like DNA methylation at CpG dinucleotide, covalent modifications of histone proteins and details of noncoding RNA’s including long ncRNA’s, miRNA. Besides importance of lncRNA’S has been discussed in dosage compensation in X linked genes with role of Xi where heavy dosage of X linked genes get compensated with role of Xist and long noncoding RNAs and further the value of genome imprinting in ART and various disorders like Beckman Wiedeman Syndrome (BWS), Russell silver syndrome (RSS) is discussed with just opposing marks on similar loci on same chromosomes. Further role of environmental stressors in stresses is discussed. Role of famines in both Chinese as well as Dutch famines highlights immediate changes can affect on future generations.
Environmental pollutants and medications may affect fetal epigenetic marks e.g., is in choline intake in pregnancy increased placental promoter methylation of cortisol regulation genes CRH and NR3IC=>improved stress response in children by lowering cortisol levels in H-P-A axis. Thus future of epigenetics research lies in understanding the effects of interaction of epigenetics and environment emphasis on fetal programming understanding and uncovering role of medicine and nutrition and assesses risk for adult onset disease.
