Re: What experiments must be done before an animal like Dolly can be cloned?

Many years worth of experiments, including many failures, went into 
developing the technology that led finally to Dolly the sheep. However, the 
specific steps were 
1) Isolate and culture cells from an adult ewe (female sheep). 
2) Isolate an unfertilezed egg from another ewe soon after ovulation.
3) Under a microscope, use a fine needle to remove chromosomes (DNA) from 
this egg. This is real tricky.
4) Fuse donor cell (cultured cell from step 1) with egg (recipient cell). 
The DNA in the nucleus of the donor cell takes over and development of the 
egg into an embryo can begin. 
5) Developing embryos must be transfered into the uterus of yet another ewe 
who will serve as surrogate mother and carry the lamb to term. 
6) Verify that the lamb has the DNA of the donor cell, and not the 
recipient or the surrogate.

So you can see, from one perspective, dolly has 3 mothers and no father.
You can also imagine that this process might not be very efficient, and you 
would be right. Only 1-2 % of fused embryos survive to term.

The above is only a broad overview. More detail can be found in a 
Scientific American article by Dr. Ian Wilmut, the scientist principally 
responsible for Dolly. The link to this is:
 
http://www.sciam.com/1998/1298issue/1298wilmut.html

Other interesting links that demonstrate that Dolly is not a fluke are:
 
http://web.missouri.edu/~psycmm/bgnews/1998/msg00020.html
 
http://www.time.com/time/magazine/1998/dom/980803/science.dolly_youre_hist14.html

Finally, if you want to know more, there are a few books out there, 
including a recent one by Dr. Wilmut and others; for a review, see:
 
http://www.crimsonbird.com/science/secondcreation.htm

Hope this helps.