Wednesday, June 11, 2003

Cloning a near miss?

I see one group is making progress on cloning the Tasmanian tiger. Except, of course, that they will have to use the egg of a different species to host the DNA. It seems plain enough that the RNA is important to the way the DNA is expressed, and we won't have exactly the right RNA for the tiger's DNA--the expression is going to have to be different.

I have no feel for how different the result will be. Between the mother and child there's some difference, but not a great deal. Within a species, I expect a little more variation, but probably not enough to cause harm. I would expect that the same embryo growing in its mother will turn out differently than if it were grown in a surrogate of the same species. Remember that CC has different markings than the cat it was cloned from. I expect there are other minor differences as well.

But from one species to another the differences could be lethal. Maybe you could clone something mammoth-like using an elephant, but I'd be astonished if you could clone a dog using a cat.

Perhaps the hope for cloning is the second generation, where the RNA ought to match the DNA.

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