Ever since Ian Wilmut, an unassuming embryologist working at the Roslin Institute just outside of Edinburgh stunned the world by cloning the first mammal, Dolly, scientists have been asking – could humans be cloned in the same way?
Putting aside the ethical challenges the question raised, the query turned out to involve more wishful thinking than scientific success. Despite the fact that dozens of other species have been cloned using the technique, called nuclear transfer, human cells have remained stubbornly resistant to the process.
Until now. Shoukhrat Mitalipov, a professor at Oregon Health & Science University, and his colleagues report in the journal Cell that they have successfully reprogrammed human skin cells back to their embryonic state.
The purpose of the study, however, was not to generate human clones but to produce lines of embryonic stem cells. These can develop into muscle, nerve, or other cells that make up the body’s tissues. The process, he says, took only a few months, a surprisingly short period to reach such an important milestone.
Nuclear transfer involves inserting a fully developed cell – in Mitalipov’s study, the cells came from the skin of fetuses – into the nucleus of an egg, and then manipulating the egg to start dividing, a process that normally only occurs after it has been fertilized by a sperm.
After several days, the ball of cells that results contains a blanket of embryonic stem cells endowed with the genetic material of the donor skin cell, which have the ability to generate every cell type from that donor.
In Dolly’s case, those cells were allowed to continue developing into an embryo that was then transferred to a ewe to produce a cloned sheep. But Mitalipov says his process with the human cells isn’t designed to generate a human clone, but rather just to create the embryonic stem cells. These could then be manipulated to create heart, nerve or other cells that can repair or treat disease.
“I think this is a really important advance,” says Dieter Egli, an investigator at the New York Stem Cell Foundation and Columbia University. “I have a very high confidence that versions of this technique will work very well; it’s something that the field has been waiting for.”…
You could be cloned right now and you would not even know it… unless you had weird flashes of intuition and visions from your clone that appeared as deja vu… but you don’t have that, do you?