Ageing's evolutionary advantages
How to explain the broad presence of two phases of ageing amongst living organisms?
The possibility of ageing being directly selected through evolution has been discussed for the past hundred years. As ageing is occurring, by definition, only late in life - i.e. after the organismal development is finalized -, many think that it cannot be actively selected for as a process. In addition, by decreasing an individual’s fitness, it is thought unlikely to be selected for. In order to explain the observation of its broad presence in the realm of life, numerous theories have been proposed in the past 75 years, in agreement with this view.
Here we build upon a model we previously published with Dr. Tristan Roget and Pr. Sylvie Méléard, a birth–death model of ageing: from individual-based dynamics to evolutive differential inclusions. Based on the Smurf 1 model of ageing2 and its broad evolutionary conservation3, this model shows that ageing - i.e. limited survival and reproduction capabilities of an organism - is under positive selection of senescence thourgh increased evolvability: ageing is not a by-product of evolution (preprint).
We are now further developing the model to include diploidy, sexual reproduction and genetic recombination. 