THE DNA of cloned embryos has been found to contain abnormalities. This could
explain why so many cloned embryos die, says the South Korean team who did the
research.
Only a few per cent of cloned embryos survive to term, and some of those that
are born are unhealthy. Researchers have suspected that misplaced methyl
(CH3) tags on DNA, which help regulate gene expression, may be partly to
blame.
Even culturing embryos in the lab can disrupt methylation
(New Scientist, 3 February, p 7).
And the nuclear transfer technique used in
cloning involves not only culturing cells, but…
