Lecture 2: Why Do We Age? Flashcards
In nature, why are fewer old individuals alive than young?
Extrinsic mortality
Is the force of negative selection stronger or weaker at older ages?
Weaker
What is the mutation accumulation theory?
Ageing is genetic and driven by accumulation of late acting deleterious genetic variants
Who came up with the mutation accumulation theory?
Medawar
What is Radom genetic drift?
Change in allele frequency in a population over generations due to random sampling
What are two consequences of random genetic drift?
Any mutation can arise and become fixed due to drift
The smaller the population, the faster the drift
Who came up with antagonistic pleiotrophy?
Medawar and later Williams.
What did Peter Medawar say?
“A relatively small advantage conferred early in the life of an individual may outweigh a catastrophic disadvantage withheld until later.”
What did George Williams say?
mutations beneficial in early life but harmful later will be positively selected for.
How have humans increased their lifespan above other animals with similar body weight?
By minimising our extrinsic mortality
Who came up with the idea of disposable soma theory of ageing?
Tom Kirkwood
What is the disposable soma theory of ageing?
Limited energy budget implies a trade-off between soma and germline
Who came up with the hyper function theory of ageing?
Mikhail Blagosklonny
What does the hyper function theory of ageing suggest?
Unabated continuation of natural functions as a source of ageing pathologies eg. run on of insulin signalling and TOR pathways
What are two extra examples of proving antagonistic pleiotropy?
Testosterone
Proinflammation
