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Human-Mouse Hybrids?
scientistguy writes "There is a remarkable story by Nicholas Wade in the early
morning edition of the New York Times about a discussion to create human-mouse
hybrid organisms. One of these techniques involves the introduction of genetically altered mouse embryonic stem (ES) cells (e.g. with
genes 'knocked-out' or replaced) into a developing mouse blactocyst to create progeny hybrid organisms. Typically, these progeny organisms are then bred to unaltered mice to see
if the genetic alteration has gone germline or is heritable. If heritable, mice can be bred and
animals which are homozygous for the altered gene can be phenotypically examined as long as the manipulation is not homozygous lethal or cause
sterility in a single copy state. Unless using
blastocysts from immunologically crippled mice, there would most likely be a recognition of non-self by murine immune cells not educated (which haven't seen during their development) to the human cells that would wipe them out. Nonetheless, it's amazing that it's
being contemplated due to the ethical implications of such an experiment. What if it were viable? What if there were more than just a few
human cells? Could it be sacrificed? ... or even experimented on further if part 'human'? Perhaps these
types of experiments are best relegated to little known, deserted islands far
away from the reaches of civilization (or perhaps regulation) ..."
Cheers Google ...
The nation of registry of choice for many ships is currently Liberia. Just think about it the next time you consider going on one of those delightful Disney cruises.
~Idarubicin
Don't be so afraid, the reporter got almost all his facts wrong. There will be 0 (zero) human cells in the chimera. That's not the way this procedure works. The genetic material is put in the blastocyst, and is then absorbed by some of the cells there. Those cells can then (in theory) produce the proteins that the absorbed genes code for. So the mouse's brain might have some human protiens in it, but it would still be a mouses's brain.
Also, the Bishop's comment about a few human cells per organ being acceptable: not the way it works. As I said, there will be NO human cells, and the modified cells will come in patches. As a modified cell in the blastocyte divides, all it's progeny will have the modifications, so you'll end up with an area in the adult organism that has the modifications. Is it really too much to ask that the people who are trying to make these ethical decisions put in the effort to actually learn what they're talking about before passing judgment?
It says:
Dipliod organisms (like all mammals including both humans and mice) have two sets of chromosomes and thus two copies of chromosome 1, two copies of chromosome 2, etc. Therefore if a particular mutation or altered gene is on, for example chromosome 3, then a mouse could have two copies of a normal chromosome (called a wild-type mouse), one normal and one altered chromosome (heterozygous), or two copies of the chromosome with the mutation (homozygous). Sometimes an animal homozygous for a certain mutation cannot survive to birth -- such a mutation is called "homozygous lethal." If the mutation is not homozygous lethal, and does not cause sterility, then one could raise a colony of mice that all have this particular mutation through selective breeding. The mice can then be examined to determine the phenotype -- or physical charactersitcs -- cause by the mutation.
and now the second sentence:
Whoever does this will have to use mice with no immune system othewise the mouse's immune system will recognise the embryonic stem cells that are introduced by the scientists as being forign and attack them. This is the same mechanism used by the body to fight off disease. (Translator's Comment: I dont think that is actualy true)