South Korea has succeeded in cloning a black cow that died three years ago with ultra-rapid freezing and thawing of eggs, local media reported Tuesday.
A research team at Jeju National University led by Professor Park Se-pill and Mirae Biotech announced over the weekend that they succeeded in developing a new freeze-and-thaw technology that allows mass cloning of animals even after their death.
The researchers transplanted somatic nuclei from a dead cow into eggs to create embryos through in vitro fertilization. Then, they froze the embryos at minus 196 degrees Celsius, and had kept them for three years before thawing and implanting them into the womb of a surrogate mother last January for the delivery of a baby cow through natural birth.
The cloned cow was born in October last year. The researchers said that DNA testing showed that the newly born cow has the same genetic blueprint as the original dead cow.
"Producing cloned embryos is hard, and what we had needed in order to enable the commercialization of cloned embryos production at times whenever we want was the establishment of the freezing- and-thawing technology. This time, we solved what had been the biggest obstacle," said Park Se-pill.
Last year, the researchers succeeded in cloning a bull that died two years ago by using fresh cloned embryos. It was the first time local researchers have cloned an animal that has been dead for some time.