Cloned calves are grown from cultured cells

Six cloned calves have been created from cells cultured in vitro for up to three months, confirming previous work showing that relatively “old” cells can be used to clone whole animals.

The achievement confirms the possibility of being able to carry out targeted genetic manipulations in vitro—taking out specific genes and replacing them with other ones—because this requires prolonged culture of nuclear donor cells.

A research team working in Japan and the …