A central goal in the modern era of evolutionary biology is to understand the genetic basis of adaptation. Microbes are ideal for such work because their genomes are small and maintaining large experimental populations is inexpensive. The difficulty in working with microbes has been identifying adaptive phenotypes beyond simple metabolic traits. The revolution in sequencing technologies make it possible to use a « reverse adaptive genetics » approach where the researcher scans genomes to identify genes with unusual evolutionary histories, identifies environmental parameters consistent with the genes, and finally tests the hypotheses by genetic manipulation. Here, I propose to apply this approach to ecologically differentiated populations of the fungal model species Neurospora discreta PS4B. My project will be based on transcriptome sequencing of populations distributed over a large latitudinal gradient. My work will advance our understanding of the mechanisms of adaptation, and the evolutionary response of organisms to global change. The outgoing phase of the project will take place in the Taylor lab (UC Berkeley), and the return phase in the ESE lab (Univ. Paris Sud). Both host groups have an excellent track record of work on the proposed research topic, and in training young researchers. My existing skills in population genetics and evolutionary ecology will be complemented by state-of-the-art approaches for analyzing genomic data and more classical experiments of molecular genetics. I will benefit from an environment where gathering and interpreting next-generation sequencing data is now routine. I will also increase my communication skills, leadership capacities, scientific network and international visibility. This fellowship will contribute to European excellence by training a researcher capable of integrating complementary approaches to address complex questions of evolutionary ecology, an expertise that is guaranteed to be increasingly valued in the future.