On Sunday morning, 23 February 1997, the world
awoke to a technological advance that shook the foundations
of biology and philosophy. On that day, we were introduced
to Dolly, a 6-month-old lamb that had been cloned directly
from a single cell taken from the breast tissue of an adult
donor. Perhaps more astonished by this accomplishment than
any of their neighbors were the scientists who actually
worked in the field of mammalian genetics and embryology.
Outside the lab where the cloning had actually taken place,
most of us thought it could never happen. Oh, we would
say that perhaps at some point in the distant future, cloning
might become feasible through the use of sophisticated
biotechnologies far beyond those available to us now. But
what many of us really believed, deep in our hearts, was
that this was one biological feat we could never master.
New life—in the special sense of a conscious being—must
have its origins in an embryo formed through the merger
of gametes from a mother and father. It was impossible,
we thought, for a cell from an adult mammal to become reprogrammed,
to start all over again, to generate another entire animal
or person in the image of the one born earlier.