User:J. C. Martinez-Garcia/Notebook/HMS Activities/2008/10/12

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Tree different cases of mutations

Today I was reading the book by Eva Jablonka -Evolution at four dimensions (MIT Press)-. In order to give an idea how mutations can work in order to find a solution to a contingent problem, the authors give the following analogy: imagine that there exists three different societies, where the differencing mechanism concerns the role of heredity in the response to contingencies. These are the three different societies:

  1. Conservatives: in this society the memory coming from the ancestors is preserved and is sacred. If the environment change and the response to this change is found in the recorded memory -the experience of the ancestors-, the tribe would survive to the change. However, if the answer is not is not in the memory, only lucky mistake would someone to find by hazard an answer an survive. The survivor will be then the new ancestor his/her answer to the concerned problem will be in his/her memory.
  2. Explorers: this society has no memories coming from the ancestors, so when a contingency arrives the response supposes that it is a novelty and try to find a response to the posed problem just sending explorers to find an answer and if they find one they will survive, but the answer would be forgotten.
  3. Interpreters: this society consider that the memory coming from the ancestors is sacred, but must be interpreted to be adapted to novelty. So, in the event of a contingency the books are read to see if there something similar to the present problem and if it the case a new solution is explored.

Taking this metaphor the authors explain that three mutational schemes can work:

  1. (Acquired mutations) Conservation-based scheme: rate of mutations is not changed, mutations are blind, and just a lucky accident will make survive the lucky individual with the lucky mutation -cheap, but only works for huge populations-.
  2. (Required mutations) Exploration-based scheme: the rate of mutation -always- blind is increased and if a good mutations is found the organism having it will survive -costly, and dangerous for a small population-; some mutations will make the mutated organisms to die in a fast way.
  3. (Interpreted mutations) Interpretation-based scheme: the rate of mutation is increased but only as a result of the interpretation of a past event.