The road to Dolly, and the path ahead and Remaking Eden: Cloning
and beyond in a brave new world
By Robert S. Schwartz, M.D.
New England Journal of Medicine
July 9, 1998
On February 27, 1997, Ian Wilmut and his colleagues at an
animal-husbandry research center near Edinburgh, Scotland, announced
in Nature the birth of Dolly. This was no mere birth notice: Dolly
was produced by fusing the nucleus of a cell from the udder of a
six-year-old sheep with an unfertilized, nucleus-free egg from another
sheep. For the first time, the restricted genetic information in
nucleus of a differentiated mammalian cell was reprogrammed to reveal
everything it knew about forming all the other cells of the body.
effect, cellular time was reversed Ñ a terminally differentiated
reverted to its primordial ancestor. Moreover, Dolly also showed
chemical messages in the cytoplasm of an unfertilized egg can awaken
the genes that differentiation puts to sleep. The identification
ovular messages that repeal the genetic injunctions imposed by
differentiation could yield immense benefits to medicine.
Dolly is an identical twin of the anonymous animal that donated
nucleus, but at her birth she was six years younger than her sister.
Therein lies the rub. Dolly is a clone, and because, imprisoned
surrogate womb, Dolly nevertheless had escaped the iron grip of
reproduction, she ignited an immediate worldwide reaction. Within
weeks of the publication of the paper by Wilmut and his colleagues,
politicians in Washington began drawing up prohibitive legislation,
in some European countries and China the cloning of humans was declared
illegal. Well-known ethicists decried the experiment on talk shows
-- Dolly reminded several commentators of Aldous Huxley's Brave
New World, The Boys from Brazil, which involved a plot to produce
clones of Adolf Hitler, or Woody Allen's Sleeper, in which the cloning
of a dictator was attempted from his nose. Meanwhile, Clonaid, a
company based in the Bahamas, was proposing to clone humans for
a mere $200,000 a copy.
Through all the uproar and self-righteous posturing, the science
created Dolly and the potential benefits of cloning mammals were
neglected or seriously misunderstood. Few who spoke out publicly
recognized the possible practical applications of the technique
cloning from an adult nucleus could advance our understanding of
normal and abnormal differentiation, aging, and cancer. Wilmut's
motivation had nothing to do with cloning humans. He wanted to improve
livestock and make genetically engineered animal factories that
would produce medically useful proteins, such as clotting factors.
Indeed, 10 months after Wilmut's paper was published, Schnieke et
al. (Science 1997;278:2130-3) reported that they had fused enucleated
ovine oocytes with fetal fibroblasts-- not with adult cells, as
Wilmut had done -- that had been transfected with the gene for factor
IX linked to the promoter for the -lactoglobulin gene for the purpose
of producing sheep that would secrete the scarce human clotting
factor in their milk.
The two books under review deal with these fascinating matters
different ways. In Clone, Gina Kolata, a well-known science writer
the New York Times, takes us on a breezy, journalistic tour of cloning.
The writing is vivid and clear. Anyone who reads her book will come
away with an appreciation of the main scientific and ethical issues.
She will engage you with the historical background and sharply etched
portraits of the leading figures in the drama. As a journalist,
has an ear for chitchat and scandal. For example, she gives us an
extended account of David Rorvik's book In His Image: The Cloning
Man (Philadelphia: J.P. Lippincott, 1978), which was advertised
true chronicle of the cloning of a mysterious, unnamed millionaire;
publisher ultimately admitted that it was a hoax. And she tells
detail the story of Karl Illmensee, who fooled the scientific community
for years with his claim to have cloned mice by nuclear transfer.
relevance of these lengthy asides to the main issues is dubious,
Clone is worthwhile as an entertaining summary of the biology of
In Remaking Eden Lee Silver, a professor in the
Department of Molecular Biology at Princeton University, gives us
a panoramic view of molecular genetics, sexual reproduction, in
vitro fertilization, and cloning. His book is an outstanding achievement.
Silver addresses the uninitiated with clear writing and straightforward
explanations of complex phenomena, but experts, especially ethicists
and policy makers, will also profit from reading this book. Any
physician should find this book remarkable. Silver analyzes the
issues soberly, often with provocative examples. Some of his cases
are hypothetical; others are drawn from real life. A high point
of the book is Silver's analysis of the
treatment of Anissa Ayala, a girl with acute myelogenous leukemia
received a bone marrow transplant from her sister; the sister had
deliberately conceived in the hope that her marrow would be
histocompatible with Anissa's. The new sister's marrow was indeed
match, and five years later Anissa, now a hematopoietic chimera,
appeared to be cured. Silver's answer to prominent ethicists who
strongly objected to this procedure is simple: what's wrong with
when the motive is love and affection? Who had the right to say
Marissa, the new sister, would not be loved for herself as much
Anissa? Silver's approach to ethical issues related to cloning and
vitro fertilization is refreshing: no nonsense, no pontificating,
the facts, just common sense. He makes his position clear with the
question, "Why is it that so many politicians seem to care
about cloning but so little about the welfare of children in general?"
According to legend, 1000 years ago King Canute tried to hold back
tides. Those who believe that they can limit the progress of science
or any other branch of human knowledge Ñ will repeat Canute's
Barbara Tuchman's classic A Distant Mirror (New York: Alfred A.
1978) and a recent translation of Johan Huizinga's magisterial The
Autumn of the Middle Ages (Chicago: University of Chicago Press,
1996) give us an extraordinary picture of the superstition, ignorance,
folly, and pestilence that ruled Western Europe 500 years ago. Five
hundred years later we have arrived at Dolly, and there is no way
of turning back. Instead, the imperative is to use our knowledge
compassion advocated by Lee Silver. Gina Kolata is wrong when she
emphasizes that by producing Dolly, Wilmut was "breaking the
nature." Nature's laws cannot be broken. What we must understand
that Wilmut's feat revealed, rather than broke, the laws of nature.
remarkable potential of this revelation is a cause for hope, not