World first: Cow cloned in new way
SYDNEY, Australia -- Australian scientists have claimed a world first, cloning a cow using a new technique that produces a healthier embryo.
Researchers from Melbourne's Monash Institute of Medical Research and the Genetics Australia Co-operative created Brandy, a two-month-old Holstein-Fresian calf in December.
Head researcher Vanessa Hall said it was the first time they had used the serial nuclear transfer technique to clone bovines, The Australian Associated Press reported.
Scientists fuse the nutrients from a recently fertilized egg to a cloned embryo before it is placed in the surrogate, thus enhancing remodeling of the DNA.
"By adding further nutrients into the cloned embryo we improve the quality of the cloned embryo," Hall told AAP.
Previously, scientists have inserted a single donor cell into an egg -- with its DNA removed -- and implanted the embryo into a surrogate mother for gestation.
This was the method used to clone many animals, such as Dolly the sheep in 1997, but very few of these implanted embryos survive full-term pregnancies.
Evidence suggests this could be due to reprogramming problems which affect the development of the placenta, Hall said.
"Although there are extra steps involved in SNT, we believe it could improve efficiencies if a larger number of healthy offspring are produced from less cloned embryos," she told AAP.
Farmers could use the new technique to clone cows in pristine condition and efficiently spread their "elite genes" through the herd, and improve the quality of a cow's milk, Hall said.
It takes two days to create an embryo, it is transferred into the surrogate a week later and takes nine months to gestate, she said.
