Washington (ddp). HIV has already around 1908 and not until 1931, as so far adopted, for the first time a people infected. This includes an American research group from a comparison of the genetic structure of different HIV variants and their counterparts from monkeys, the SI viruses. Then, the variety of genetic structures of most common type of HIV, HIV-1, was so great that more than previously suspected 30 years since the first appearance in humans must be passed at the beginning of the 1960s. The less common type of HIV-2, however, was transferred in may actually only in the 1930s by the apes to humans. It comes from a SI-virus, which infected monkeys contrary to previous assumptions not for millions of years, but only a few hundred years ago. Reports on the work of the team to Michael Worobey of the online service of magazine «science». Among the examined samples was also material from lymphoid tissue that was 1960 been stored in the University of Kinshasa. It contains HI viruses type 1 and is thus only the second HIV detection, dating from the pre-1976. The already existing genetic diversity discovered Marlea Gemmel, an employee of Worobey when she compared the DNA of the virus from a 1959 taken from blood sample with the. Using the data of today’s HI viruses, the scientist could also calculate the approximate time, where began the development of HIV-1 in humans. Also the development of HIV-2 was slightly differently than in the past adopted, as Joel Wertheim reported, another employee of Worobey. In particular his ancestor, so the SIV strain, HIV-2 originated from which is of interest. Because monkeys often carry the viruses in the body, but virtually never fall ill from AIDS, scientists had previously suspected monkeys and viruses had used to each other in the course of a joint development lasting millions of years. When Wertheim now compared the SI viruses from green monkey, Mangabey and macaques, he stated however, that the pedigree of viruses not in the same places as the primates had branches. However, this would be an indispensable prerequisite for the theory of the long joint development. Instead, so Wertheim concludes from his data, the virus was probably only at the beginning of the 19th century on the macaques of, and from there it jumped to humans about 125 years later. To know the origin of HIV, it is important for two reasons, writes «science». On the one hand, these viruses illustrate how and how often pass diseases from animals to humans. On the other hand, the results to understand HIV and AIDS help. If, for example, was not the long period of adaptation, which made immune to SIV, the monkey must be – searched for other factors, and these can show may be new therapeutic approaches.