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In 1997, Dolly the cloned sheep began a biological revolution. She showed us the way to
physiologically dedifferentiate already committed somatic cells, opening the gate to a
whole new world of possibilities in the study of basic biological mechanisms that touch the
origins of life at its core. It is clear that cloning vertebrates using somatic cells is here to
stay. Unfortunately, at this time, we know little about how this process works, and it is difficult
to imagine all the applications this technology will bring to fruition. This book tries
to address some of these questions.
Part I of Principles of Cloning explores the basic known biological processes and lays
out critical points to consider when interpreting cloning experiments that are now being
conducted. The nucleus itself, chromatin structure, epigenetic changes, and the role of the
egg are emphasized. Part II describes the methods utilized during cloning in an attempt to
make them available to students and professionals who are interested in nuclear transfer
techniques in vertebrates. Parts III–V contain analyses of species that already have been
cloned and species that are still being studied, including nonhuman primates. We are
delighted to say that the contributors in these sections published the first articles on most
of these species. Experts in the area have also contributed to the applications of cloning
covered in Part VI; we expect this part of the book to communicate the benefits of cloning
to society in the medical and agricultural fields. Part VII addresses the ethical concerns
evoked by this technology and is followed by an analysis of what the future may bring.
We hope this book challenges readers, encouraging them to think beyond the cloning
procedure itself to the creation of new individuals or pluripotent stem cells. Interesting questions
regarding the mechanisms of dedifferentiation must now be addressed; the answers
will perhaps allow scientists to recreate the same phenomenon in a more consistent and
simpler way. |
