Scientists from the University of California, for the first time, raised a sheep embryo, which contained human cells. The results of the research were presented as part of a speech at the conference of the American Scientific Society in Austin.
Experts have placed human stem cells in a sheep embryo. In total, the chimeric embryo developed for 28 days. This was enough to demonstrate that embryos could well become full-fledged living things, then the experiment was stopped due to the restrictions in force in the country.
The number of human cells in an embryo is small - one in ten thousand. Therefore, the embryo would never turn into a "sheep with a human face or brain."
It is assumed that such a study will make it possible to grow full-fledged human organs inside animals suitable for subsequent transplantation to a patient. However, this requires that the embryo contains one percent of human cells.
In January 2017, biologists from the United States, Spain, and Japan created pig-human hybrids for the same purposes. As a result, precursor cells of various types of tissues, in particular the heart, liver and nervous system, were formed in the porcine embryo. The pig-human hybrids were allowed to develop for three to four weeks, after which, for ethical reasons, they were destroyed.