The genome is a common feature of all cellular organisms and contains a comprehensive record of evolution. At a closer look, the genome is in fact a ‘genomic microcosm’ – a smörgåsbord of interactions among/between host genes and parasitic genes, such as transposons and viruses. We study how these genomic parasites impact genome structure and speciation of birds, crocodilians, and parasitic nematodes. Beware, some of these jumping genes even jump between genomes!