Explanation of this Research
In terms of the impact of these proposals on
research in the UK, we feel it is very important that the debate
uses correct terminology. Animal eggs are used to create cloned
human embryos as lab models to study disease.
A rabbit or cow egg is taken and almost all
genetic info removed (all except the mitochondrial DNA). Concurrently
a patient with the disease being studied, for example Alzheimer's
or motor neurone disease, has a skin cell removed. The nucleus
of the patient's cell, which contains the genetic material, is
put into the "empty" animal egg. An electric current
is then used to trick the egg containing the human genetic material
into dividing to become an early embryo (genetically the embryo
will be 99.5% human). Stem cells are extracted from the embryo
and are studied for no more than 14 days to understand how cells
from a patient with a disease differ from those without disease.
The embryo is then destroyed.
Are these chimeric embryos? Or, are they hybrid
No and no. A chimeric embryo has separate cells
from two different species. A hybrid embryo genetic material from
two different speciesi.e. the egg and sperm cells are from
The cells produced in this research contain
more than 99.5% human DNA, the remainder being mitochondrial DNA
from the animal cell. A more specialised term for these embryos
could be "mammalian incubated human nuclear embryos".