Variation and adaptive potential in bacterial gene pools exposed to different mechanisms of mutation

Anne-Marie Veenstra-Skirl, room 5172.583 tel 38086 email This email address is being protected from spambots. You need JavaScript enabled to view it.

Introduction

Mutations generate novel, heritable variation in phenotypic traits, thereby supplying the raw material for adaptive evolution. Neo-Darwinian theory posits that mutations occur randomly with respect to their fitness consequences to the organism. Yet, mutations are not necessarily random in other respects as well, given that they carry signatures of the molecular mechanism by which they were generated. Each different mechanism of mutation produces its own characteristic statistical pattern in phenotypic effect sizes, pleiotropic effects and epistatic interactions, which shape the genetic architecture of traits. Based on this observation, it has been suggested that the mechanisms of mutation can significantly bias microevolutionary processes and influence the future adaptive potential of populations.

Aim

This project is a collaboration between the institutes GELIFES and GBB and shall shed light on whether different mutation mechanisms shape the genotype-phenotype-map of bacterial populations in a  way that their adaptive potential varies for different selective environments. The molecular construction of required strains is performed in the MolGen-labs, particularly, the development and characterization of mutator strains. Evolution experiments in continous chemostat-systems are performed in the lab of the TRES-group of GELIFES.

Techniques

Molecular biology techniques in L. lactis and E. coli, cultivation in continuous chemostat systems

References

Rokyta, D.R., et al, 2005, An empirical test of the mutational landscape model of adaptation using a single-stranded DNA virus, nature genetics, Vol. 37, No. 4, p. 441-444

Machielsen, R., et al, 2010, Indigenous and environmental modulation of frequencies of mutation in Lactobacillus plantarum, Applied Environmental Microbiology, Vol. 76, No.5, p. 1587-1595

El Karoui, M., et al, 1998, Identification of the lactococcal exonuclease/recombinase and its modulation by the putative Chi sequence, Proceedings of the National Academy of Sciences of the United States of America, vol. 95, No. 2, p. 626-631

Barrick, J.E. and Lenski, R.E., 2013, Genome dynamics during experimental evolution, Nature Reviews:Genetics, Vol.14, p. 827-839