Steve Schaffner
Posts: 13
Joined: June 2009
|
| Quote (Zachriel @ June 14 2009,08:47) | If the genome is 3e8 bases in size (or any such large number) and there is an average of one mutation per child, then we expect that ~1/3 of the children will *not* have mutations. If each mother produces 6 children, then chances are that each new generation will include many individuals
without mutations. (E.g. mice often have several litters of 4-10 pups.)
|
True, although that's probably not a good model for humans, who have something between 1 and 3 deleterious mutations (probably) per birth, and more likely close to the top end than the bottom of the range. That doesn't mean that the population has to collapse genetically. It just means that in the steady state, everyone is carrying a fair number of deleterious mutations, with those having the most being the least likely to reproduce.
| Quote |
If we use truncated selection, heritability=1, mutations=1, seed=30, all else default, this is what we see.
|
Note that the population survives only because of truncation selection, which is not a realistic process for such slightly deleterious mutations. In this model, each individual will have on average one new mutation with a negative selection coefficient of something like 10-6 or 10-7, but selection is nonetheless effective enough to perfectly sort the fitness of the individuals and eliminate only the least fit.
| Quote |
It's interesting to see how the deleterious mutations ride along with the beneficial mutations until fixation before being weeded out.
|
Yes. Selective sweeps in action.
|
