The study of genetic variation is one of the main purposes of the evolutionary biology. According to the neutral theory of molecular evolution the main part of the genetic diversity is due to genetic drift. In the recent years also the interaction between recombination and natural selection, called linked selection play a fundamental role in shaping the genetic diversity at genomic level. This is interesting specially in plants where the different types of mating system influence the patterns of linked selection on the genome. In this project we analyse 12 populations of Brassicaceae’s species with different mating system (autogamy or allogamy). We analyse the signature of linked selection across the genome comparing the difference between the selfing and the outcrossing species. To detect the this signature we perform population genetics analysis on genome resequencing data and to assess the significance we perform coalescence simulations. The outcome of this project could give us a better understanding of the forces that shape the genetic variation on the genomes.