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This assumes that by removing the disadvantage that it automatically confers an advantage to those that are treated. They still need a genetic advantage to flou

by kls 13y ago

This assumes that by removing the disadvantage that it automatically confers an advantage to those that are treated. They still need a genetic advantage to flourish. Granted there may be an uptick in people that carry the defect by the shear fact that it is no longer an disadvantage but that does not translate into a society where everyone suffers from this defect. Unless they carry some latent advantage that could not be recognized because of the sever genetic disadvantage. I prefer to look at it as we have moved past that disadvantage in much the same way that we moved passed smallpox, some of smallpox was nature and immunity the other half was eradication. I see us doing the same thing, just speeding up the timetables now that we know some of the mechanics to do so.

jkn 13y ago
I know next to nothing about the dynamics of gene transmission (if someone does please shed some light), but it seems quite obvious that the less evolutionary pressure you have against a gene, the more prevalent it will become. My intuition is that evolutionary pressure works against entropy. Without the pressure, the genome would evolve towards a state of maximum entropy, i.e. a particular mutation would reach a prevalence of about 50%. But of course there will always be some sort of evolutionary pressure.
- Dylan16807 13y ago
  I would expect more of a random walk. I suppose that very slowly genes would mutate by themselves, but as far as having certain genes spread, two kids multiplied by 50% chance equals the same number of people with the gene, generation after generation.
  - jkn 13y ago
    Well I was actually thinking about mutations :) Let's consider a simplified model, where there are only two different bases (A and G instead of A, T, G, C) and assume that the probabilities of mutations A->G and G->A are the same. Let's consider a single base mutation[1]. No matter what the mutation probability is, and no matter what the initial distribution is, I expect that the population will converge to about 50% A and 50% G. I guess you would agree. Now if we make this very wrong model a bit less wrong by including the four base types A, T, G, C, we can expect that each allele will be found in about 25% of the population. And that is for single base mutations only. A mutation that depends on the precise value of 5 different bases would be displayed by a much smaller share of the population (1/4^5 = 0.1% I guess). Of course people don't get born with fully random genomes like that, the vast majority of these mutations would not yield a living embryo. But still, the intuition we can get from this is that without evolutionary pressure, a particular mutation will eventually be found in a fraction of the population that is inversely proportional to the complexity of the mutation (in most cases that would be far from the 50% of my initial intuition). No idea how close these layman's speculations are from the reality... [1] Such as the gene that determines the type of ear wax: http://udel.edu/~mcdonald/mythearwax.html http://udel.edu/~mcdonald/mythearwax.html

by kls 13y ago

jkn 13y ago

I know next to nothing about the dynamics of gene transmission (if someone does please shed some light), but it seems quite obvious that the less evolutionary pressure you have against a gene, the more prevalent it will become. My intuition is that evolutionary pressure works against entropy. Without the pressure, the genome would evolve towards a state of maximum entropy, i.e. a particular mutation would reach a prevalence of about 50%. But of course there will always be some sort of evolutionary pressure.

Dylan16807 13y ago
I would expect more of a random walk. I suppose that very slowly genes would mutate by themselves, but as far as having certain genes spread, two kids multiplied by 50% chance equals the same number of people with the gene, generation after generation.
- jkn 13y ago
  Well I was actually thinking about mutations :) Let's consider a simplified model, where there are only two different bases (A and G instead of A, T, G, C) and assume that the probabilities of mutations A->G and G->A are the same. Let's consider a single base mutation[1]. No matter what the mutation probability is, and no matter what the initial distribution is, I expect that the population will converge to about 50% A and 50% G. I guess you would agree. Now if we make this very wrong model a bit less wrong by including the four base types A, T, G, C, we can expect that each allele will be found in about 25% of the population. And that is for single base mutations only. A mutation that depends on the precise value of 5 different bases would be displayed by a much smaller share of the population (1/4^5 = 0.1% I guess). Of course people don't get born with fully random genomes like that, the vast majority of these mutations would not yield a living embryo. But still, the intuition we can get from this is that without evolutionary pressure, a particular mutation will eventually be found in a fraction of the population that is inversely proportional to the complexity of the mutation (in most cases that would be far from the 50% of my initial intuition). No idea how close these layman's speculations are from the reality... [1] Such as the gene that determines the type of ear wax: http://udel.edu/~mcdonald/mythearwax.html http://udel.edu/~mcdonald/mythearwax.html