It dates back about 300 million years ago, the first appearance of the insect virus, in exactly the same time that insects have evolved. Together, they continued to live in a 'synchronized'. These are the conclusions of a study on some parasitic wasps produced by researchers at the University of Tours in France and published in the latest issue of the journal of the Academy of Sciences of the United States, PNAS. The basis of the work, researchers led by Julien teez''have traveled in time'', based on the study of the genetic heritage of some types of wasps and viruses that infect up to reconstruct the story. In''DNA of all living things are parts, even large, which are supposed to be the legacy of ancient infections suffered by our ancestors, by some viruses,''said microbiologist Michael La Placa, University 'di Bologna . By analyzing the distribution of these shares common among different species and fossils' can reconstruct the evolutionary history. Going back in time, the French researchers have come to the conclusion that some mutations in the DNA of modern insects can be traced to the early common ancestor lived 310 million years ago, in the middle Palaeozoic Era.''Particularly in insects and 'can be observed the presence of long DNA sequences due to old infections,''he said La Placa,''so as to lend itself to a phylogenetic analysis, in order to establish a real tree.'' Many kinds of wasps lay their eggs inside caterpillars and inject paralyzing toxin in their bodies that allows larvae to feed on the host without risk. It 'has long been known that these substances are poisonous legacy' left by genetic infected with a virus that 'the ancestors of those wasps million years ago, it's a fossil that is genetic and' transformed into a powerful weapon for these insects. In turn, the virus also needs the wasps to survive, because 'the DNA of these insects causes' that the virus can only develop in the ovaries. In the study, researchers analyzed the DNA of certain insects, relating it to the genetic sequences of their viruses, so they 'restored a kind of parallel tree insects and their pathogens, and that allowed us to verify their origin simultaneously.