Teruhiko Wakayama and his colleagues at the Center for Developmental Biology in Japan report on 3rd of this month in the Proceedings of the National Academy of Sciences the successful cloning of mice using genetic material from bodies frozen for 16 years. Till then, cloning had been possible only with the use of live, intact cells.
Wakayama and his team used two methods of nuclear transfer to create these Frankenmice. In one case, nuclei from both brain and blood cells in the frozen mice were injected—still frozen—into female reproductive cells that had their nuclei removed. Those cells were than allowed to advance into the marula/blastocyst stages and the resulting embryonic stem cells were removed and used to create clones. In a another case, the reproductive cells were immediately placed in surrogate mice to be carried to term. Both methods produced live, healthy clones.
It has been more than a year since the cloned mice were created and although it is uncertain how long they will live, they are still spinning in their exercise wheels. Clones were made from genetic material that had been frozen for one week, one month, three months, and 16 years, and it looks like the length of time in the freezer has no effect on the success of the cloning.
It was previously thought that “most if not all” cells from mammals would be ruined if frozen, unprotected, but these new results open up the possibility for protecting endangered species through catalogs of frozen tissue to use in the future. Such “frozen zoos” are already in progress.
And while Wakayama can’t say for sure, it even raises the prospect of "resurrecting” extinct animals that have left frozen remains.
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