Jan. 17, 2008 -- Researchers today reported that they have made embryonic clones from donated eggs and men's skin cells.

The clone developed into hollow balls of cells (blastocysts) in the researchers' lab.

This is the first time the cloning technique has been done using adult cells (the male skin cells) instead of embryonic cells, according to the scientists, who included Andrew French, PhD, of Stemagen, a stem cell research and development company in California.

French and colleagues call their work a "prelude" to the development of cloned human embryos to generate embryonic stem cells for stem cell research.

In other words, they've shown that they can make embryonic clones from adult cells, but they haven't yet gotten those embryonic clones to make embryonic stem cells.

Here's how the process worked.

Step 1: Remove the nucleus, which contains DNA, from the donated egg.

Step 2: Insert the skin cell's nucleus into that egg.

Step 3: Coax the egg to start dividing.

The basic idea is to make the egg start developing with the donor's DNA instead of the egg's own DNA.

French's team reports developing five blastocysts using skin cells donated by two men. Only one of those blastocysts was confirmed by DNA tests to be a true clone, with no genetic material from the donated egg.

Details of the experiment appear in today's online edition of Stem Cell.

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