#GeneticDrift

This is part of an undergraduate practical looking at #NaturalSelection vs #GeneticDrift. We subculture the flies every ~2 weeks: at each subculture, we select a random sample of the last generation to found the next. The tubes start out with mostly white-eyed flies, who find it difficult to spot mates, which is selectively disavantagous. We add a couple of red-eyed flies to that first generation to see whether they become more numerous over time.

The neutralist-selectionist debate needs moderating, and this paper makes some good contributions, but ultimately disappoints. It defends #NeutralTheory as acknowledging #BackgroundSelection, but does not qualify that this is only a limited form of background selection - one with strong deleterious effects and Ud<1, such that background selection can be captured by a 1-locus model of random #GeneticDrift with lower #EffectivePopulationSize. https://onlinelibrary.wiley.com/doi/10.1111/brv.13010?af=R 1/n

Background selection at unlinked sites might not matter if it can be well captured by #EffectivePopulationSize describing #GeneticDrift in a 1-locus model. So we added a figure to demonstrate that this isn't the case. 6/5

@cyrilpedia Not a high bar - #GeneticDrift sensu strictu isn't very important. The real question is randomness due to mutation + recombination + migration (origination rather than subsequent drift of variants) vs the external environment. A bit of a hobby horse of mine: https://www.cell.com/current-biology/fulltext/S0960-9822(11)00882-7 and https://onlinelibrary.wiley.com/doi/abs/10.1002/bies.201100178

@arlin Can this be summarized by saying that mutation + genetic drift creates traits that may later be maintained by positive selection?

#NaturalSelection, #Darwinism, #GeneticDrift, #NeutralEvolution