The first animal created by putting the DNA of one species into the egg of another is due to be born in the next week. Some scientists hope the technique could be used to bring extinct animals back from the dead.
Noah is the clone of a rare wild ox, the gaur. He was created by fusing skin cells from a gaur that died in 1993 with cow eggs stripped of their nuclei 鈥� the same technique used to create Dolly the sheep.
His foster mother, a cow called Bessie, is due to give birth 鈥渋n the next week or so鈥�, says Robert Lanza of Advanced Cell Technology in Massachusetts, US.
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Lanza鈥檚 team had predicted a birth last November, but he told New 杏吧原创: 鈥淭he published gestational period for the gaur was reported at 270-280 days. But recent data from the US suggest that in fact it鈥檚 over 300 days.鈥�
Multiple pregnancies
Creating Noah wasn鈥檛 easy, says Lanza. Eight foster cow mothers became pregnant with the embryo clones. But five miscarried, and two the pregnancies were terminated early, so the scientists could monitor the development of the embryos.
鈥淭hose numbers actually look very good,鈥� says Lanza. 鈥淯sually it takes 10-20 pregnancies to get one live animal 鈥� and that鈥檚 from a cow embryo in a cow, not from one species to another.鈥�
The team now plan to use normal goat eggs to clone the bucardo, a Spanish mountain goat that became extinct last January.
Cells from only one dead female are available for cloning. Critics of the project pointed out that the team will not be able to clone males, and so create breeding pairs.
But Lanza believes this problem can be overcome: 鈥淢odifying the chromosome to create a male goat will require some work 鈥� but it is definitely something that will be feasible in the next couple of years.鈥�
Related story: Raising the dead, 9 October 2000