Placing human DNA into cow or rabbit eggs in order to make hybrid cloned embryos to produce stem cells for research doesn't work because the animal eggs don't reprogram human DNA in the correct way to generate stem cells, U.S. researchers say.
"Instead of turning on the right genes, it turns out the animal eggs actually turn them off," senior study author Dr. Robert Lanza, of Advanced Cell Technology in Worcester, Mass., told the Associated Press.
The findings were published online Monday in the journal Cloning and Stem Cells.
Scientists would like to find a way to use animal eggs because it's difficult to get human eggs for research. While some scientists have managed to create human-animal hybrid embryos, there's no widely accepted report of harvesting stem cells from them, the AP said.
The U.S. researchers' conclusions were disputed by a British scientist who has government permission to attempt to create hybrid embryos.
"The idea that this is the nail in the coffin for hybrids is grossly overstated," said Stephen Minger of King's College, London, the AP reported