In recent years, the advancements in aging research have led to a deeper understanding of the aging process and have also greatly changed our perception towards aging. In addition, the Human Genome Project has provided information on the human genome and has provided a study base for the elucidation of the molecular mechanisms underlying aging. It is interesting to note that the causative gene of Hutchinson-Gilford progeria syndrome was identified at the same period of the Human Genome Project completion, and it was expected that all the genes related to the human aging process would be identified. However, many phenomena regarding the molecular mechanisms underlying aging still remain unknown. Understanding these mechanisms is necessary in order to control aging process.