A study published Monday has found that eggs from cows, rabbits and other animals are not a good source for creating embryonic stem cells, the master material that could one day repair tissue damage, replace organs, and reverse degenerative diseases.
But, in the same study, US researchers made a significant advance in the cloning of human embryos, which could be a path to producing a host of patient-specific treatments.
"This study shows for the very first time that cloning really works and that DNA is reprogrammed," said co-author Robert Lanza, the chief scientific officer at Advanced Cell Technology.
Lanza and his team were able to replace the nucleus of a number of embryos and bring the clones to the morula stage, where they had divided into eight to 16 cells.
In the human embryos, they were able to prove that the DNA was reprogrammed because the same genes were activated as in a normal embryo.
But something went wrong when the nuclei of rabbit, mice and cow embryos were replaced with a human nucleus.
"We would get these beautiful little... see more