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永利集团网址:Clones may not grow old before their time

点击量:   时间:2019-03-07 11:20:01

SIX calves from Connecticut, cloning’s latest stars, should finally answer the question of whether clones age prematurely. Dolly the sheep, the first animal to be cloned from an adult cell, appears healthy so far. But there are signs that the wear and tear accumulated by that donor cell could make her age before her time: Dolly’s chromosomes are shorter than normal sheep of the same age, which is a sign of cellular ageing (New Scientist, 29 May 1999, p 12). Even if Dolly dies young, however,