LONDON, Aug. 1 (Xinhua) -- "Xiao Xiao," which means
"tiny" in Chinese but represents a big victory for scientists as the world's
first cloned mouse from iPS cells, was highly praised by an expert at Britain's
Roslin Institute where the first cloned mammal Dolly was born.
"Xiao Xiao," which means "tiny" in
Chinese but represents a big victory for scientists as the world's first
cloned mouse from iPS cells, was highly praised by an expert at Britain's
Roslin Institute where the first cloned mammal Dolly was born. (Photo:
Sciencenet.cn) Photo Gallery>>>
"Most research progresses in small steps. Xiao Xiao
represents a jump forward," said Bruce Whitelaw, head of the Division of
Developmental Biology at the Roslin Institute, and editor-in-chief of the
journal Transgenic Research.
This is because Xiao Xiao finally proved that iPS
cells, the abbreviation of induced pluripotent stem cells, are truly
pluripotent. Stem cells are cells that can differentiate into specialized cell
types for organisms to grow or repair themselves. In a developing embryo, stem
cells can differentiate into all of the specialized embryonic tissues, therefore
the embryonic stem cells are called pluripotent.
In 2007, Japanese and American scientists declared at
the same time that they induced skin cells into the status of pluripotent
independently, which implicated that an adult cell could be reprogrammed to its
"embryonic status" and then develops to a full functional creature.
"iPS cells are truly a revolution," said Whitelaw.
Since then scientists have developed many types of cells from iPS cells, e.g.
heart cells, blood cells, cornea cells and nerve cells. But though researchers
all around the world tried hard, no one had yet reported a full functional
mammal from iPS cells.
This undated photo provided by animal
clone scientist Zhou Qi of the Institute of Zoology in Beijing shows the
mouse Xiao Xiao or "Tiny" from the induced pluripotent stem (IPS) cells.
Two teams of Chinese researchers have created live mice from IPS cells,
answering a lingering question about the developmental potential of the
cells, according to a press release published online by Nature on July 23,
2009. (Xinhua/Zhou Qi) Photo
Gallery>>>
In
that sense, Xiao Xiao declared the victory of the revolution as two Chinese
groups reported "mice made from induced stem cells" online in Nature and in Cell
Stem Cell respectively on July 23.
Whitelaw said, "The world must now believe that iPS
cells can be truly pluripotent."
The Chinese group of Qi Zhou and Fanyi Zeng reported
27 live births including Xiao Xiao in one of the two papers. Though some died
after just two days and some displayed physical abnormalities, a number of mice
have passed one of the most fundamental tests of health: all 12 mice that were
mated produced offspring, and the offspring showed no abnormalities. The team
said it now has hundreds of second-generation and more than 100 third-generation
mice.
"The true test of pluripotency is the ability to
derive an entire fully functional animal from the pluripotent cell. This animal
must develop and grow then age. It must be able to reproduce and this is exactly
what Qi Zhou and Fanyi Zeng have shown in their paper," Whitelaw extended his
special appreciation on that.
Though Dolly was created by the cloning technology of
nuclear transfer, while Xiao Xiao was by introducing iPS cells into an embryo,
the resulting animals in both cases are clones, Whitelaw said.
This undated photo provided by animal
clone scientist Zhou Qi of the Institute of Zoology in Beijing shows the
mouse Xiao Xiao or "Tiny" from the induced pluripotent stem (IPS) cells in
its three-month old. Two teams of Chinese researchers have created live
mice from IPS cells, answering a lingering question about the
developmental potential of the cells, according to a press release
published online by Nature on July 23, 2009. (Xinhua/Zhou Qi) Photo
Gallery>>>
"Yes,
Xiao Xiao received the torch lit by Dolly," he commented while reviewing the
history of clone.
About practical implication of Xiao Xiao, Whitelaw
said it showed us the prospect to translate iPS technology into other animal
species such as livestock.
Whitelaw highly praised the work of Chinese
scientists.
"The two Chinese groups in achieving this success
have shown persistence and dedication to the task. They have achieved what other
groups all around the world have not managed yet. They deserve the credit for
this achievement," Whitelaw said.
This undated photo provided by animal
clone scientist Zhou Qi of the Institute of Zoology in Beijing shows the
mouse Xiao Xiao or "Tiny" from the induced pluripotent stem (IPS) cells in
its three-month old. Two teams of Chinese researchers have created live
mice from IPS cells, answering a lingering question about the
developmental potential of the cells, according to a press release
published online by Nature on July 23, 2009. (Xinhua/Zhou Qi) Photo
Gallery>>>
