Tuesday, 15 March 2005

Of Mice and Men

From the UK Telegraph :
It will look like any ordinary mouse, but for America's scientists a tiny animal threatens to ignite a profound ethical dilemma.

In one of the most controversial scientific projects ever conceived
Someone shoot the inveterate (accent on the "vet") punster
... a group of university researchers in California's Silicon Valley is preparing to create a mouse whose brain will be composed entirely of human cells.

Researchers at Stanford University have already succeeded in breeding mice with brains that are one per cent human cells.

In the next stage they plan to use stem cells from aborted foetuses to create an animal whose brain cells are 100 per cent human.
At hearings in Washington last October, Prof Weissman argued strongly against a ban on "chimera mice". He believes that the mice would behave like any others, but said that he would monitor the experiment closely and destroy them at the slightest suggestion of human-like brain patterns.
Thereby grossly compounding the original offence.

Not that he has to worry - and he knows that, or he wouldn't have said such a thing. The mouse's brain is still only the size of, well, a mouse's brain. It's not true to say it can have no more intellect than a human foetus of the same size : a human foetal brain hasn't got the wiring, the interconnection of neurones that makes a brain functional. All it has is potential, something the mouse brain does not. The set of reasonable expectations (assuming it develops into a functional organism) runs all the way from a "developmentally challenged" mouse to one that has significant improvement in cognition. Why? Because the phenotype (ie the body of the animal) is derived from the genotype (genetic inheritance) plus the environment. Genetically identical stem cells develop into different bodies in different environments.

Identical Twins are *not* quite Identical. Genetically, yes, they're a clone of two genetically identical individuals. And the environment of the mother's womb will be very nearly identical for both. But not quite absolutely identical. In extreme cases, one can end up damaged, degraded or just plain different due to environmental factors ( mother's drug use, disease ), while the other remains "normal".

Place a human-derived neural stem-cell in a mouse's womb, and it will respond to the rodent chemical triggers it's given during gestation, not the human ones it doesn't get. How it will respond - that's something we don't know, and it is almost certainly very useful to know this. It will teach us a lot about human neural development that we probably can't find out any other way.

But had I been on the ethics committee, I would have done my darnedest to find logical fact-based reasons for what my intuition is telling me: that this is dangerous and ethically dubious. In all honesty, I would have had to recuse myself from judgement, as I'm so prejudiced (as in "pre-judging and liable to ignore inconvenient facts").

I firmly believe that this is a Very Bad Idea Indeed, but it's a case of :
I do not like thee, Doctor Fell.
The reason why, I cannot tell.
But this I know, and know full well,
I do not like thee, Dr Fell.
- Tom Brown
I don't have the intellectual honesty and rigour to rise above my prejudices. I do have the minimal personal honesty though to recognise my prejudices for what they are, while still believing that they're justified. I just don't know how to justify them. But enough of me, the important thing is what is about to happen in the Stanford Labs. The more people who know about this, IMHO the more likely we are to accurately determine if this is ethical or not.

I do know this: that had the experiment involved non-human foetal brain tissue - such as from a cow - I would have some qualms, but from what I know could be persuaded that the potential gain outweighs the potential risk. I also know that had the experiment involved using mouse-derived neural stem cells in a human womb, I'd oppose it with all the resources within my power, up to (but not including) violence. As it is, this is uncomfortably borderline.

The use of aborted foetal tissue is another matter - but one that I'm comfortable with. I'm anti-abortion as a method of contraception, but once the deed is done, have no ethical qualms about salvaging the best of a bad situation. If you like, it would be no worse than harvesting transplant tissue from murder victims. The crime is the murder, not the harvest.

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