Patent ID: 7335811

Claim:
A method for nuclear transplantation comprising collecting donor cells in G1 phase comprising, in the order mentioned, the steps of: (1) culturing mammalian fibroblast cells on a support in the presence of an agent for synchronizing cell cycle to metaphase; (2) shaking said support and recovering cells detached from said support; (3) recovering cells having a diameter of not less than 20 μm from the cells recovered in said step (2); (4) culturing said cells recovered in step (3) so as to allow each of the cells to divide into two cells; and (5) recovering uniformly divided cells in step (4) separately; (6) transplanting said donor cell recovered in step (5) or nucleus thereof into an enucleated oocyte; and (7) culturing the resulting nuclear transferred cell to allow it to divide; said method further comprising, between said step (1) and step (2), the additional steps of shaking said support; discarding cells detached from said support together with the culture medium; and culturing cells remaining on said support in the presence of said agent for synchronizing cell cycle to metaphase, said additional steps being carried out once to thrice.