The Hallmarks of Aging
There are multiple aging theories, but one of the most popular and well supported is the Hallmarks of Aging, a 2013 paper that defined aging as nine distinct categories (hallmarks) and explained how these interact with each other to drive the development of age-related diseases. This framework gives researchers insights into how they might directly intervene against these aging processes to prevent age-related diseases.
Why we age: Telomere Attrition
Telomeres are DNA regions located at the ends of a chromosome. Their normal length is 8-10 thousand base pairs, yet they consist of repetitions of a single sequence: TTAGGG. Telomeres do not code for proteins, but they protect chromosomes from erroneously bonding with different molecules and with each other. Telomere attrition limits the number of times our somatic cells can divide, slowly leading to dwindling populations of cells in vital organs.