Appendix: Telomere Dynamics, Cancer Suppression, and Evolutionary Insights

Telomere Length, Body Size, and Cancer Risk

One striking evolutionary pattern is that large-bodied, long-lived species tend to have very different telomere biology compared to small, short-lived species. In general, mammals above a certain size (~5–10 kg) repress telomerase in their somatic cells and have shorter baseline telomere lengthspubmed.ncbi.nlm.nih.gov. This leads to replicative senescence (cells permanently stop dividing after a number of divisions) and is thought to be an anti-tumor adaptation in big animals with many cellspubmed.ncbi.nlm.nih.gov. In contrast, small rodents (e.g. mice) maintain high telomerase activity and long telomeres throughout the bodypubmed.ncbi.nlm.nih.gov. Because of their small size, even