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Project Progress

In the first year, we have made limited progress, because it took a while to recruit a postdoc to work on the project. However, I now have a postdoc in place who is working on the project, and we I expect us to make rapid progress. We have selected 3 adaptive lineages that were isolated from our previously published experimental evolution work (Levy et al, 2015, Nature 519, 181-186.). These lineages have been sequenced, and we have both presumptive gain of function and loss of function beneficial mutations, which affect either the Ras/Protein Kinase A signaling pathway, or the Tor signaling pathway. Each of these lineages has been backcrossed to the ancestral strain that contains a “landing pad”. These have then been sporulated, so that we have isolated individuals with both the beneficial mutations and a blank landing pad. The landing pad allow us to rebarcode each strain (~500,000 individual barcoded lineages per mutant), so that we can track the emergence of beneficial mutations as each mutant is independently experimentally evolved. Prior to starting the experimental evolutions, we will first perform pairwise fitness competitions between independent segregants of each lineage against a fluorescently marked ancestor strain, to unequivocally prove that as predicted, the mutations do provide a fitness benefit.