Generations Of Mice Cloned
An international team has cloned not one mouse, but dozens, from adult mice, U.S. researchers said Wednesday. It's the latest breakthrough in cloning, outlined today in the journal Nature.
CBS News Correspondent Elizabeth Kaledin reports it is called Honolulu cloning, developed by a team of researchers at the University of Hawaii.
Ryuzo Yanagimachi of the University of Hawaii and colleagues said they had cloned several generations of mice and hoped their method would prove to be a breakthrough for both animal breeding and basic scientific research.
"The method used to create these mice is really remarkably different and new and we think it's an advance," said cloning researcher Dr. Tony Perry of the Babraham Institute in Cambridge, England, who worked on the study.
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The researchers extracted cells containing the genetic code from a brown mouse and microscopically injected them into the egg of a black mouse whose own genetic code had been removed. Then they implanted the egg into a white surrogate mother mouse, who then gave birth to a clone of the original brown mouse.
Unlike the method used to create Dolly the sheep, which produced only one animal and lots of doubt about whether it could be repeated, researchers in Hawaii produced more than 50 cloned mice. Some of them are even clones of clones of clones.
Yanagimachi and Teruhiko Wakayama, a Japanese researcher who developed the Honolulu technique, took the nucleus out of an adult mouse cell and injected it into the egg of another mouse, which has also had its nucleus removed.
He used cumulus cells, which surround the developing eggs inside the ovaries of female mice. The first baby mouse, born October 3, was named Cumulina, after the type of cell used.
Like most other cells, cumulus cells have "differentiated". Although each cell contains the complete DNA blueprint needed to create a whole animal, it has turned off this facility and will split to create only other cells of its type.
"Our method differs substantially from previous techniques. Earlier procedures generated clones either by injection or fusion of embryonic or fetal cells or by the fusion of adult cells, which is how Dolly the sheep was created," Yanagimachi said in a statement.
Earlier this month Japanese livestock researchers said they also used the electrofusion method to clone twin heifers from an adult cow.
"The report today is important because it transformed cloning in mammals from a hypothesis to a hard fact," Dr. Elizabeth Lacey, molecular biologist.
That's important because scientists predict the ability to create whole populations of genetically identical animals will allow them to study, treat and even cure certain diseases.
Thee is even hope the technology could be used to help rescue and clone endangered species. The potential applications are enormous. But just because Honolulu cloning works on mice doesn't mean it will work on larger mammals and many scientists say that's where the real benefits of cloning are hidden.