Question to the Department of Health and Social Care:

To ask the Secretary of State for Health, pursuant to the Answer of 7 April 2014, Official Report, column 42W, on in vitro fertilisation, if he will provide specific references to the available evidence that no genomic DNA is found in the mitochondria but only in the cell nucleus; how their consideration that mitochondrial DNA is not part of the genome relates to the presentation of data on the human genome in the ENSEMBL and OMIM databases; what precise genetic modifications are applied to the eggs or embryos that would prevent any nuclear DNA from the egg or embryo donors from being inherited by the resulting child; and if he will make a statement.

We have been advised by the Wellcome Trust that whole mitochondrial DNA genome sequencing has revealed no evidence of nuclear genomic DNA inside mitochondria and data on the human genome available in the ENSEMBL and OMIM databases confirms that there is no nuclear genomic DNA in the mitochondria.

Inheritance of nuclear DNA from the donor egg is prevented in the Maternal Spindle Transfer technique through the removal of the spindle from the donor egg. Given that the nuclear DNA in the form of condensed chromosomes is attached to the spindle, nuclear genomic DNA from the donor will be removed and not inherited by the resulting child. Techniques that allow the visualisation of condensed chromosomes in eggs are used to ensure that all the chromosomes are removed.

For embryos used in the Pronuclear Transfer technique, the nuclear genomic DNA is enclosed within the nuclear membrane of the maternal (egg-derived) and paternal (sperm-derived) pronuclei. The donor nuclear genomic DNA will be removed when the pronuclei are removed.

There is no universally agreed definition of genetic modification in humans. The Government has adopted a working definition for the purpose of taking forward the draft mitochondrial donation regulations, that genetic modification involves the germ-line modification of nuclear DNA that can be passed on to future generations. Therefore, the Government does not accept that mitochondrial donation amounts to genetic modification.