Can we breed humanoid animals by manipulating human stem cells?

Answer

Goodbye dear,

Unfortunately, the articles you provide are more fiction than reality. But as often there is a kernel of truth behind it!

It’s not that we can suddenly make puppies with a human head and the like. One is misled by the term “Chimera”, as it sometimes appears in Greek mythology… But modern chimeras are actually something completely different. A chimera is an organism that is actually a mixture of different organisms. This also occurs in nature, there have been a few cases in recent history:

– a mother did not have the same genome as her children. Then it turned out that the DNA sample taken from her jaw tissue was different from the sample used to determine her heredity in relation to her offspring. This was quite surprising, because this woman has two “sets” of DNA and is actually two people in one…

– a lady who had two blood groups at the same time, then research showed that cells from her twin brother were living in her body. These had become mixed during the early development of the two fetuses. It had also suddenly been discovered that with organ transplantation one actually becomes a chimera.

Anyway, these stories are nice to show what a modern chimera is. They have been used in science for quite some time. In the 1960s, artificial chimeric mice were already made. Nowadays, these are frequently used to carry out targeted gene research and to switch off certain genes with great precision. This way people quickly know what the effects are and what the gene actually does, where it is expressed, etc…

Well, one step further is “humanizing” animals, especially mice. This is already happening, for example, by replacing the spleens of mice with human tissue (or a combination of these). This is very difficult and still quite new, but it has enormous advantages. In this way one can better mimic the human immune system and thus work more accurately to develop therapeutic antibodies, for example. The big problem with antibodies from animal sources is that, like any pathogen, they are foreign to our body and therefore also trigger an immune response. If we can use human antibodies right away, then that problem goes away, which is really a huge advantage…

But rest assured, there are strict ethical laws on the creation of chimera, even more so on the use of humanized cells. Usually, artificial chimera with human stem cells and lead to embryos must not exceed the age of 14 days and must be destroyed… And even if the embryo were to develop into a full-fledged life form, the chance is very small (almost non-existent) that it would survive unless the two species are very similar genetically. They once succeeded in artificially combining a sheep and a goat, but I don’t immediately see a human being walking around with a tiger skin, so to speak ;).

kind regards,

Kenneth Verheggen