1.   He inserted them into pig eggs and transferred the resulting embryos into surrogate mothers, who gave birth to the four cloned piglets.

2.   In each case, human DNA was inserted into fertilized pig eggs, and the resulting swine produce both human and porcine proteins.

3.   The Scottish company researchers began with cells from an adult animal and cycled the transplanted nucleus through two different pig eggs.

4.   They removed the nucleus, which contains DNA, and injected it into a pig egg from which the nucleus had been removed.