Epigenetic changes in health and disease: DNA Methylation in human development, infection and non-communicable diseases

Following completion of the sequencing of the human genome in 2001 attempts were made to decipher functional units imprinted in the genome, their regulation, and deregulation that caused disease. The genetic and epigenetic information laid down in the genome were recognized and their functions investigated. The coding genes laid down the blueprint for the synthesis of all proteins necessary for functioning while epigenetic markers in the form of methylated CpG dinucleotides on the genome commanded their expression at appropriate times enabling human to live through its full life cycle. Zygote genome formed following fertilization was found to be globally hypomethylated and was pluripotent. However when it was subjected to cell specific differentiation the genome underwent hypermethylation giving rise to different morphological and functional characteristics. Promoter regions of some of the genes were activated while some others were silenced. These were the dictums of internal and external signals elicited through epigenetic marks laid down in the human genome. Infections and chronic non-communicable diseases such as cancers, cardiovascular diseases etc were found to be the outcome of aberration in genomic DNA methylation. These epigenome changes being reversible act as feasible targets to achieve normalcy. If detected early preventive and curable action could be implemented.