Bacteria often exchange their genome between them. However, scientists did not believe that bacterial genes were found in the genome of more complex organisms. This is why they are surprised when the DNA of the vinegar fly contains the complete genome of a bacterium of the genus Wolbachia. Now, researchers believe that the presence of bacterial genes, especially in reptiles and amphibians, in animal DNA will probably be quite common, and they want to investigate the importance of this gene transfer in evolution.