Presentation Detail

Population Genetics and/or Genomics, Theoretical

Kosheleva, Katya [1], Desai, Michael [2].

The Dynamics of Genetic Draft in Rapidly Adapting Populations.

In rapidly adapting populations, evolutionary dynamics are strongly affected by the accumulation of beneficial mutations on competing genetic backgrounds, causing erratic fluctuations in the frequencies of observed mutations. This randomizes the time to fixation of successful mutations and leaves distinct signatures on patterns of genetic variation. This`genetic draft' is at least as important as genetic drift in populations where many beneficial mutations segregate simultaneously. We describe how this additional source of stochasticity affects the forward-time dynamics of site frequencies in rapidly adapting asexual populations. We calculate the probability for mutations at polymorphic sites to shift to different frequencies over a characteristic timescale, and use these probabilities to derive several quantities of interest, including the sojourn time of mutant alleles, the expected fixation time of successful mutants, and the site frequency spectrum of beneficial and neutral mutations. These results may be viewed as an extension of Gillespie's original model of genetic draft (which features a neutral locus linked to a single strongly selected locus) to the case where many strongly selected beneficial mutations segregate simultaneously.

1 - Harvard University, Physics, 15 Oxford Street, Cambridge, MA, 02138, USA
2 - Harvard University, Organismic and Evolutionary Biology, 435.20 Northwest Labs, 52 Oxford Street, Cambridge, MA, 02138, USA

Keywords:
Adaptation
Genetic Draft
Clonal Interference.

Presentation Type: Regular Oral Presentation
Session: 5
Location: Alpine A and B/Snowbird Center
Date: Saturday, June 22nd, 2013
Time: 9:00 AM
Number: 5003
Abstract ID:812
Candidate for Awards:W.D. Hamilton Award for Outstanding Student Presentation