8-Humans: Baby doctor reveals cloned human embryo
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TITLE: Baby doctor reveals cloned human embryo
SOURCE: The New Scientist, UK, by Philip Cohen and Damian Carrington
DATE: Apr 9, 2003
------------------ archive: http://www.gene.ch/genet.html ------------------
Baby doctor reveals cloned human embryo
Controversial reproductive scientist Panayiotis Zavos has published a
short report and picture of what he claims is "the first human cloned
embryo for reproductive purposes".
The single four-day-old embryo, comprised of 8 to 10 cells, is revealed
in a commentary in Reproductive BioMedicine Online.
Zavos says the embryo was created by somatic cell nuclear transfer
(SCNT), the same technique used to make the famous cloned sheep Dolly. In
SCNT, a cell is fused with an egg stripped of its own genetic material.
The egg and cell used were donated by a woman who wants to have a child
using SCNT, says Zavos. He is based in Kentucky, but he says this work
was performed outside the US. Human reproductive cloning is illegal in
many countries. The embryo was then frozen for further study and
analysis, says Zavos, and full results will later be documented in peer-
Robert Edwards, a pioneer of IVF and chief editor of Reproductive
BioMedicine Online, says in an accompanying commentary that this "first
formal report on steps leading towards human reproductive cloning" is
"welcome and timely, especially since so much secrecy has characterised
Zavos says he will screen cloned embryos for defects before implantation.
But Edwards says determining the safety of human reproductive cloning
procedures will be "an immense and highly complex task". The results of
cloning in many animal species "remain disastrous", he adds.
Developmental biology expert Azim Surani, at the University of Cambridge,
UK, is unimpressed by the scant data presented so far.
"It is not clear to me at all if this paper represents a real advance in
knowledge," he writes in a third commentary in the same journal. For
instance, Zavos does not verify that the embryo was actually produced by
nuclear transfer, rather than an egg that started dividing on its own.
Surani also points out that Zavos has tended towards optimistic
representation of cloning data - even when it comes from other labs.
Zavos cites the efficiency of mouse cloning as 56 per cent. Yet most
experts agree mouse cloning efficiency - measured by live births - has
stuck below two per cent, despite years of experience.
The new data on Zavos's cloning experiments have also failed to sway the
majority of scientists and ethicists who believe that attempting to clone
humans is either too dangerous or simply immoral.
Zavos likens the criticisms to those made in the 1970s against IVF
procedures, which have since led to the birth of a million people. But
Surani says IVF replicates in the laboratory a process that occurs
naturally in the body. "By contrast, cloning is quite different. There is
no natural counterpart to this process," he argues.
Zavos's embryo is only slightly more advanced than the six-cell cloned
human embryos reported by the Massachusetts-based biotech company
Advanced Cell Technology in 2001.
However, the ACT embryos were not created for reproductive purposes, but
to study the potential of cloning to make replacement tissues for
transplants. Chinese researchers also interested in therapeutic cloning
say they have matured cloned human embryos to more than 100 cells, but
have not provided evidence to back up those claims.
Zavos first came to public attention when he teamed up with the
controversial Italian fertility doctor Severino Antinori and proclaimed
the duo would clone a child by the end of 2002.
Later Zavos split with Antinori and dismissed his colleague's reports of
clone pregnancies. Clonaid, a company created by a UFO cult known as the
Raelians, claims to have already cloned several babies, but these reports
remain completely unsubstantiated.