Preprint · Aug 28, 2019
Multi-generational human provisioning predicts longer telomere length in Bali’s temple macaques (Macaca fascicularis), consistent with the ‘thrifty telomere’ hypothesis
By Rej PH, Klegarth AR, Koenig CMR et al.
There is mounting evidence to suggest that short telomere length (TL) increases an organism’s susceptibility to disease and accelerates aging. However, it is not well understood why these effects do not select for longer telomeres. The ‘thrifty telomere’ hypothesis suggests one possibility: while longer telomeres improve an organism’s ability to repair tissue through less constrained cell proliferation, cell proliferation requires energy that might be more adaptively used for other physiological processes. Thus, natural selection may favor shorter telomeres in low resource environments. Here we present an experimental assessment of the thrifty telomere hypothesis carried out across urban long-tailed macaques (Macaca fascicularis) in Bali, Indonesia and Singapore. Groups of macaques in Bali have been variably provisioned by humans for over 1000 years and are somewhat genetically distinct. Thus, current provisioning levels likely index past natural selection. Conversely, in Singapore, groups are less genetically distinct, and regular human contact/provisioning is a much more recent phenomenon. Therefore, differences across Singaporean groups are more likely to be due to environmental exposures affecting TL within a generation. We measured TL in 168 wild macaques from across both islands. Two different measures of anthropogenic contact were collected from the Bali and Singapore animals. Consistent with the thrifty telomere hypothesis, we observed a positive association between TL and anthropogenic contact within Bali, but not Singapore. Inconsistent with predictions, there were no differences in TL across islands. These results provide tentative support for the thrifty telomere hypothesis, suggesting that increased energetic availability may allow selection for longer telomeres.