Creating Chimera: of mice,cows and men

UK scientists have applied for permission to
create embryos by fusing human DNA with cow eggs.

The news item on BBC's site caught my eye immediately, prompting bizarre images of cowpeople to fly willynilly through my brain. Shaking them off (with some difficulty, I might add) I stopped to consider several questions. Firstly, just how on earth could that even be done? I know that simply posing the question risks explanations that I won't (with my grade-school grasp of the question) have a hope in hell of understanding, but I'm a fool-hardy person, sometimes given to intellectual risk taking (as in the watching of BBC's hilarious sitcom, Shameless ), so I gave it a shot.

Well, the bare facts are not all that difficult: after removing the DNA from a cow's egg, a hole is drilled into it by a laser , (which gives new meaning to the concept of penetration in reproduction) into which is put the nucleus of a human skin cell . After a few days the embryo, which will be 99.9% human, is destroyed and the stem cells extracted. Scientists in the UK are successfully using this process with mouse cells and want the go-ahead to use human cells.

So, now I'm curious about that remaining .1% . Just what does "outside the nucleus" mean? Is there then no influence or genetic expression in the created embryo? Or will there be only minimal expression, say just a little patch of black skin or a rather m-m-mellow voice? Of course the plan is for an early 'harvest', therefore the question becomes moot (one can only hope). The big issue is : What is the nature of that created embryo? Is it human , by virtue of that 99.9%? Or is that .1% of bovine, outside the nucleus though it may be, enough to classify that incipient bundle of life as animal?

If it's animal , we can possibly dodge some of the issues that have plagued scientists seeking readily available sources of human stem cells with which to conduct medical research, much of which promises to be our best hope of effective treatments for Alzheimer's , Parkinson's and Multiple Sclerosis as well as a host of other debilitating diseases. If it is human , however, the same objections to developing and subsequently destroying the embryos that are presently raised to prevent the use of human stem cells harvested from the unwanted embryonic by-products of fertility efforts in jurisdictions like the United States, will apply.

These are difficult questions, which we-the-people tend to leave up to the scientists and the politicians, if only by default. We need to at least consider them.

http://news.bbc.co.uk/2/hi/health/6121280.stm