#geneticdrift — Public Fediverse posts

How do ranges form and persist? Hancock et al., using shovel bugs that live on sandy beaches, discovered that when dispersal is asymmetric, it can drive the production of range edges.

Read now ahead of print!
https://www.journals.uchicago.edu/doi/10.1086/741060

#RangeEdges #GeneticDrift #EEB

Relaxed Purifying Selection is Associated with an Accumulation of Transposable Elements in Flies.

#Transposons #PurifyingSelection #GenomeSize #GeneticDrift #EffectivePopulationSize #Flies #Drosophila

https://academic.oup.com/mbe/article/42/6/msaf111/8149079

This is part of an undergraduate practical looking at #NaturalSelection vs #GeneticDrift. We subculture the tube of 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 a lower #EffectivePopulationSize describing #GeneticDrift in a 1-locus idealized 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