IT’S back to the drawing board for cloning pioneers trying to explain why only 1 to 5 per cent of pregnancies result in healthy, cloned animals.
Their previous explanation was that genes in cloned embryos get “mis-programmed” during the process of making a cloned embryo. But Xiangzhong “Gerry” Yang at the University of Connecticut in Storrs and his colleagues found that the pattern of activated genes was almost identical in week-old cow embryos, regardless of whether the embryo was created through cloning or produced by insemination of a cow. Only 50 of the 5174 genes analysed differed in activation, less than 1 per cent of the…
