Chimera is an organism that contains at least two genetically different groups of cells originating from different organisms. There are some rare natural occurances of these, even humans, where two non-identical twins have merged into one as embryos.

There are srtificial chimeras as well. For example geep, a sheep-goat chimaira. This is different from sheep-goat hybrid, which may result when sheep and goat mate: in geep there are groups of cells with entirely sheep and others with entirely goat DNA, while in hybrid the DNA is homogenous throughout the body.

Recently BBC has reported that some researchers in UK have applied for a licence to use cow egg cells as a replacement for human egg cells – mainly because of the high demand and short supply of human egg cells. The nucleus of the egg cells would of course first be be emptied.

BBC points some ethical considerations on this. “It would, though, technically be a chimera – a mixing of two distinct species into one.” I don’t see how. Even if there were traces of DNA in that cell outside the nucleus, I think it should be classified as a hybrid.

Another BBC article tells more about this and some more chimera type experiments. To quote:

One of the latest chimeras to hit the headlines was created by scientists in Korea. They sparked controversy when they injected human embryonic stem cells into developing mouse embryos.

The finding that these the cells were then distributed throughout the mouse’s body, including the brain, caused public outrage, and the scientists later abandoned the experiments as the protests increased.

I wonder when they start asking questions, how ethical it is to

1. do this type of superexpensive research at all, due to it’s ultimately relatively small use, considering the prospects of civilization as a whole?
2. develope and practise medicine that increases the expected lietime of masses, given the strain it sets on the capability of civilization to survive?
3. ask questions like this in the first place?