Viola Nolte

Abstract Background:Transposable elements (TEs) are DNA sequences that can move within a host genome. Many new TE insertions have deleterious effects on their host and are therefore removed by purifying selection. The genomic distribution of TEs thus reflects a balance between new insertions and purifying selection.

1 INTRODUCTION Environmental conditions during development have a significant impact on adult phenotypes and fitness (e.g. (Dufty et al., 2002)). The high population densities during juvenile development observed in nature (e.g. Atkinson, 1979) have triggered continued interest in plastic phenotypic responses to this environmental stressor (Pearl & Parker, 1922).

Abstract Experimental evolution combined with whole-genome sequencing is a powerful approach to study the adaptive architecture of selected traits, in particular when replicated experimental populations evolving in opposite selective conditions (e.g. hot vs. cold temperature) are compared. Nevertheless, such comparisons could be affected by environmental effects shared between selective regimes (e.g. laboratory adaptation), which complicate the interpretation of selection signatures.