Geneticists have obtained a "real" chimera monkey for the first time
Chinese researchers have created a full-grown macaque using stem cells and the embryo of another individual of the same species. This is the world's first chimeric primate with a large proportion of foreign cells obtained by live birth.A few years ago, scientists have already introduced a small portion of foreign genetic material into animal samples and obtained from them full-fledged individuals. But this time, a team of researchers from the Chinese Academy of Sciences grew an organism with a very large (more than half) share of genes from another individual. The findings are presented in the journal Cell.
Stem cells from a seven-day embryo of a macaque crab-eating monkey (Macaca fascicularis) were injected into another five-day embryo of the same species. The two organisms were not related to each other. Later, the female monkey gave birth to a fully formed male cub.
The injected stem cells formed 92 percent of the baby's brain tissue and totaled 67 percent of his body. These numbers were helped by a fluorescent green-colored protein that the scientists used to stain the pluripotent cells. After the cub was born, the researchers saw that green cells were "scattered" throughout its body: for example, they were clearly visible on the fingertips, in the eyes. The analysis showed that the donor cells were present in a wide variety of tissues in the monkey, forming between 21 and 92 percent of these structures.
The scientists themselves seem to be stunned by the result: they did not expect that the individual will be born not only a full-fledged being, but the introduced embryonic cells will go to the development of the fetus in such a record amount.
Alas, the baby lived only 10 days - he began respiratory failure and hypothermia (drop in body temperature below normal). Therefore, the monkey had to be put to sleep. The exact cause of the cub's deteriorating health is not yet clear, but scientists suggest that it may be due to epigenetic differences between the different cell types of the chimeric individual.
Note that chimerism also occurs in humans, but it is natural: for example, in the 46,XX/46,XY scenario. Such people are viable and their mental abilities are quite normal, although the size and morphology of the genitalia are usually abnormal.
Despite the death of the first truly chimeric macaque obtained by artificial means, the researchers believe that their work is very important: it can help create animal models close to humans for the study of neurological diseases and other biomedical research. In the past, chimeric animals have been derived from rodents (which cannot be considered a species close to humans), but this is the first time such a large-scale work has been done for monkeys.