We talked about two prominent evolutionary theories of aging:
mutation accumulation and antagonistic pleiotropy.
To compare and contrast these theories,
this programme simulates the change in the
number of mutations that contribute to aging
in a hypothetical population over many generations.
Here, we monitor the number of mutations that manifest their effect
at three different stages post reproductive maturity: early, mid and late.
To keep it simple, let's think of aging as accumulation of
later-life acting deleterious mutations.
Bear in mind that the mutation accumulation theory is
only concerned with
deleterious
mutations that affect the organism's life negatively.
Meanwhile, according to the antagonistic pleiotropy theory,
a given mutation is pleiotropic, meaning it has both
beneficial
and
deleterious
effects.
Finally, remember that evolution typically happens over many generations.
You can go back in time using the Generation slider below.
Questions
1. Mutation accumulation
1a. How does the number of deleterious mutations change over increasing age of effect? Explain why we see this pattern.
1b. Alter the level of extrinsic mortality and describe the effect this has on mutation accumulation for each stage (early, mid, late).
At which life-stage is selection against deleterious mutations the strongest? Explain why.
2. Antagonistic pleiotropy
2a. Compare the pattern for deleterious mutations in the antagonistic pleiotropy model of aging to that observed in mutation accumulation. What is different? Why might this be?
2b. Compare the distributions of beneficial and deleterious mutations. What pattern do you observe? Can you provide an explanation for this?
2c. Compare and contrast the distributions of beneficial and deleterious mutations under the scenarios of low versus high extrinsic mortality.
What do you notice under each scenario? How might you explain your observations?