ABSTRACT
Experimental evolution is becoming a popular approach to study genomic selection responses of evolving populations. Computer simulation studies suggested that the accuracy of the signature increases with the duration of the experiment. Since some assumptions of the computer simulations may be violated, it is important to scrutinize the influence of the experimental duration with real data. Here, we use a highly replicated Evolve and Resequence study in Drosophila simulans to compare the selection targets inferred at different time points. At each time point approximately the same number of SNPs deviated from neutral expectations, but only 10 % of the selected haplotype blocks identified from the full data set could be detected in the first 20 generations. Those haplotype blocks that emerged already after 20 generations differ from the others by being strongly selected at the beginning of the experiment and displaying a more parallel selection response. Consistent with previous computer simulations, our results confirm that only Evolve and Resequence experiments with a sufficient number of generations can characterize complex adaptive architectures.