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Cloning Hits A Barrier At Sixth Generation
New York - Sept. 20, 2000 Cloned animals may be harder to clone again, say researchers who have struggled to produce six generations of cloned mice. The result hints at a hidden defect in animals produced by the technology. Teruhiko Wakayama of the Rockefeller University in New York and his team say the mice in their experiment appeared healthy. But it became harder to clone them with each successive generation. Only one mouse was produced in the sixth generation despite massive effort. And this lone clone was eaten by its foster mother. "Either it was sick and died or the foster mother didn't like it and destroyed it," he says.
Nuclear transfer Wakayama and his team first hit the headlines two years ago when they cloned the mouse Cumulina, the first clone produced from an adult animal since Dolly the sheep. They also announced the remarkable feat of serial cloning. By using donor cells from each successive generation, they produced four generations of clones. In their new report, they report for the first time that they could not produce mice past the sixth generation.
Hidden flaw But neither one of these possibilities seems to be true. In fact, the mouse telomeres seem to grow slightly with each generation. And all the clones could navigate mazes and pass other cognitive tests with flying colours. They also aged gracefully - one fifth generation mouse is alive and well in mouse middle age, 18 months. Wakayama's team continues to search for some hidden flaw. "Our results suggest clones are accumulating some abnormality," he says. The fact that the final animal was eaten by its foster mother might suggest the defect is obvious to rodent senses, if not human testing. Source: Nature (vol 407, p 318) This article appeared in the September 20 issue of New Scientist New Scientist. Copyright 2000 - All rights reserved. The material on this page is provided by New Scientist and may not be published, broadcast, rewritten or redistributed without written authorization from New Scientist. CommunityEmail This Article Comment On This Article Related Links SpaceDaily Search SpaceDaily Subscribe To SpaceDaily Express Dirt, rocks and all the stuff we stand on firmly
Magnetic Reconnection Region Larger Than 2.5 Million Km Found In The Solar Wind
Paris (ESA) Jan 12, 2006Using the ESA Cluster spacecraft and the NASA Wind and ACE satellites, a team of American and European scientists have discovered the largest jets of particles created between the Earth and the Sun by magnetic reconnection. This result makes the cover of this week's issue of Nature. |
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