Telomere biology and the molecular basis of aging.

Process of aging is regulated on the level of organism, clones and cellular level. Genes regulating aging on the individual (organism) level are detected in unicellular fungi. Mutations of such genes may lead to life lengthening by 60%. A similar gene is found in mice. Aging at the clonal level takes place by means of telomere shortening--that of DNA regions close to chromosome endings. Telomere shortening results in the chromosomes instability, their breaks and mutations, this apparently being a mechanism responsible for the increase of cancer incidence at advanced age. Telomerase is an enzyme responsible for the stability of the telomere length, supporting proliferation and by this that of life. This explains the increase of telomerase activity practically in all cases of malignant tumors. Aging is regulated by molecular components of cell cycle on cellular level.