Methylation Level Differences between the Housekeeping and the Specialized Genes Identified during Ontogenesis

The genome methylation is one of the leading areas in the study of aging. The theoretical model we proposed earlier explains aging by redistribution of limited resources between two main tasks of the organism: its self-sustenance based on the function of the housekeeping gene group (HG) and functional differentiation provided by the IntG integrative gene group. To test our model, we used methylation level data of 100 genes, (gene body and its promoter) of 50 in the HG group and 50 in IntG. We found reliable differences ( p<0.0001) between our groups in the level of absolute methylation values, more pronounced in the promoters of the studied genes. We showed their significant decrease in IntG with age in contrast to HG, where this level remained relatively constant. The decrease in methylation in the IntG group is indirectly confirmed by the analysis of data variance, which also decreased in the genes of this group. The increasing imbalance between HG and IntG by methylation levels suggests that this IntG-shift reflects a side effect of the ontogenesis program and its connection to the main cause of aging.