Monday's story on successful primate cloning appears to be true. Nature published the paper today along with a non-technical summary.

The researchers, led by Shoukhrat Mitalipov, discovered that dyes and ultraviolet light normally used when removing the egg's nucleus harm the cell. They minimzed damage to the egg by using the Oosight machine instead, resulting in the creation of 35 blastocysts from 304 attempts using DNA adult skin cells. Mitalipov's team then attempted to extract stem cells from 20 of the best blastocysts, with two attempts bearing fruit and producing embryonic stem cell lines.

While the rate of creating blastocysts using adult DNA is less than half that of using fetal genetic material, some researchers are very excited by the news. Robert Lanza told Nature that this accomplishment is "like breaking the sound barrier" in primate cloning and that he hopes this success encourages regulators to change their rules and allow the work in humans.

Nature's summary did include one confusing note toward the end when explaining why reproductive cloning is a bad idea right now:

So far, the recipe Mitalipov used for his embryonic stem-cell lines has not worked for reproductive cloning. This April, the team tried to transfer 77 embryos into about a dozen surrogates. The embryos ranged in their stage of development: some were 2 days old, some were 5-day-old blastocysts. "But no pregnancy made it even to day 25," says Mitalipov.

This paragraph implies that Mitalipov's cloning method has created at least 77 embryos, compared to the 35 mentioned earlier. If those 77 were transfered into surrogate mothers to initiate pregnancies, and 20 were used for stem cell extraction, that means the improved nuclear transfer technique has succeeded at least 97 times.

This could mean the Oregonian team has derived more stem cell lines since the paper was initially submitted. I'm awaiting word back from Oregon Health & Science University, where Mitalipov works, for clarification.

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