Genetic Draft and Quasi-Neutrality in Large Facultatively Sexual Populations

Biology – Quantitative Biology – Populations and Evolution

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

Includes supplement as appendix

Scientific paper

Large populations may contain numerous simultaneously segregating polymorphisms subject to natural selection. Since selection acts on individuals whose fitness depends on many loci, different loci affect each other's dynamics. This leads to stochastic fluctuations of allele frequencies above and beyond genetic drift - an effect known as genetic draft. Since recombination disrupts associations between alleles, draft is strong when recombination is rare. Here, we study a facultatively outcrossing population in a regime where the frequency of out-crossing and recombination, r, is small compared to the characteristic scale of fitness differences \sigma. In this regime, fit genotypes expand clonally, leading to large fluctuations in the number of recombinant offspring genotypes. The power law tail in the distribution of the latter makes it impossible to capture the dynamics of draft by an effective neutral model. Instead, we find that the fixation time of a neutral allele increases only slowly with the population size but depends sensitively on the ratio r/\sigma. The efficacy of selection is reduced dramatically and alleles behave "quasi-neutrally" even for Ns>> 1, provided that |s|< s_c, where s_c depends strongly on r/\sigma, but only weakly on population size N. In addition, the anomalous fluctuations due to draft change the spectrum of (quasi)-neutral alleles from f(\nu)\sim 1/\nu, corresponding to drift, to \sim1/\nu^2. Finally, draft accelerates the rate of two step adaptations through deleterious intermediates.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

Genetic Draft and Quasi-Neutrality in Large Facultatively Sexual Populations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Genetic Draft and Quasi-Neutrality in Large Facultatively Sexual Populations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Genetic Draft and Quasi-Neutrality in Large Facultatively Sexual Populations will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-189768

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.