Citation
TP53 copy number expansion is associated with the evolution of increased body size and an enhanced DNA damage response in elephants
TL;DR
Elephants have 20 copies of p53 tumor suppressor gene (humans have 1)
This research revealed that elephants have 20 copies of the p53 tumor suppressor gene compared to just 1 in humans, explaining their remarkably low cancer rates despite large body size and long lifespan. It demonstrates how evolution tunes mutation-related mechanisms (DNA repair, tumor suppression) to organism characteristics.
The finding supports the chapter's argument that mutation rates and their consequences are evolvable traits, calibrated by natural selection to ecological context - large, long-lived organisms need enhanced protection against the cumulative effects of mutations.
Key Findings from Sulak et al. (2016)
- Elephants have 20 copies of p53 tumor suppressor gene (humans have 1)
- This explains low cancer rates despite large body size
- Enhanced DNA damage response evolved with increased body size
- Demonstrates evolution tuning mutation-related mechanisms to organism characteristics
- Applies to understanding 'Peto's Paradox' (large animals don't have proportionally more cancer)