As a follow-up to an 8 year long evolution experiment in Drosophila melanogaster (https://doi.org/10.1111/evo.14021), we swapped either the sex chromosomes or autosomes between the selection regime and the control regimes. We did this to look for signatures of co-evolution between the autosomes and the sex chromosomes, as this might explain some of the more curious phenotypic results we got. Aside from two phenotypic assays, we also wanted to look at changes in expression between the swapped populations. To do so, we have sequences pools of 30 flies of both sexes and will look for signs of compensator selection, once we have the count data.