快猫短视频

LAST week鈥檚 news of the birth of Tetra, a rhesus monkey created by 鈥渆mbryo
splitting鈥�, was heralded as a step towards human cloning. But while it is the
first time the technique has been used successfully in primates, it won鈥檛 bring
human clones any closer.

Gerald Schatten of Oregon Regional Health Science University in Portland and
his colleagues used a different technique from the one that created Dolly the
sheep. This could never be used to clone adults. The team split early embryos
into individual cells, and grew them into new embryos鈥攁 process that
mimics the way natural twins develop.

In fact, researchers have already tried to do the same in humans. In 1993, a
team in Washington DC split human embryos that had defects incompatible with
life. Schatten鈥檚 study shows that it is hard to get live births even with
healthy embryos. He implanted some two dozen embryos, but Tetra was the only one
to survive.