60 DISCOVERMAGAZINE.COM
LEFT: BEN CURTIS/PA IMAGES/GETTY IMAGES. RIGHT: QIANG SUN AND MU-MING POO/CHINESE ACADEMY OF SCIENCESMEDICINE
A potential HIV vaccine and new ways to decode gut woes raise hopes,
while cloning passes a key milestone. BY MARK BARNA
It’s a Twofer:
First Primates
Cloned
Zhong Zhong and Hua Hua have
made medical history as the irst
cloned primates.
The feat, described in
January in the journal Cell by
a team of Chinese scientists,
is a milestone for biomedical
research. It could potentially
lead to the development of new
treatments for human disease.
But it also makes ethicists
nervous about where this all
might lead. Do Zhong Zhong and
Hua Hua presage the dawn of
human cloning?
Born in 1996, Dolly the sheep
was the irst cloned mammal,
and was followed by many more,
including dogs, rabbits and pigs.
But researchers were unable toclone primates because the genes
involved didn’t react well to the
procedure. Over the years, a
handful of research institutions
have tried and failed to birth a live
monkey clone.
The successful team, atShanghai’s Chinese Academy
of Sciences, used the same basic
method that created Dolly but
had failed in subsequent primate
cloning attempts. It’s called
somatic cell nuclear transfer and
involves transferring DNA from
adult cells into eggs that have
had their own DNA removed.
Without the addition of sperm,
the eggs are stimulated chemically
to develop into an embryo that’sa clone of the DNA donor. The
embryo is then placed into a
surrogate for gestation.
The researchers modiied the
approach in two important ways,
however. Rather than use adult
cells in the DNA transfer, they
used fetal cells, which react better
to chemical stimuli for embryo
development, says Mu-ming Poo,
director of the academy’s Institute
of Neuroscience and a co-authorCloned monkeys Zhong
Zhong (left) and Hua Hua,
at 8 and 6 weeks old, respectively.Dolly the sheep, born in 1996, was
the first of many cloned mammals.