December 4, 2022

Playing with fire

Hi there,

One of America’s leading bioethicists, Thomas H. Murray, of The Hastings Center, has called for a national debate on so-called “mitochondrial transfer” (see below). This is a highly controversial technique for allowing parents who might pass on a genetic disease due to defective mitochondria. It is being studied in both the US and the UK.

What I have realised in the few news stories I have written on this topic is that its ethical assessment depends on how the technique is framed.

This begins with its name. Is it really just transferring 1% of genetic material to an embryo – which the name implies? If so, perhaps it’s not a big deal – although, as I recall, 1% or so is the difference between us and chimpanzees. Or is it really a transfer of the 99% of genetic material which resides in the nucleus to a new cell membrane? (See below). That sounds a bit more serious, doesn’t it?

Then there are the benefits. The child, conceived through IVF, is supposed to have healthy mitochondria and will be free from the genetic disease passed on by its mother. That frames the mitochondria as interchangeable computer chips. But is that true?

In one of the stories below US biologist Maureen Condic challenges this assumption. She says that there are dangers in this technique. What if some of the old mitochondria remains in the cell and clashes with the new mitochondria? Plus, the DNA in the nucleus and the DNA in the mitochondria are supposed to be a perfect match. What guarantee is there that they will function properly? Is it possible that the technique might create a new genetic disease?

I don’t know the answers to these issues, but I do know that these difficulties do not fit within the frame of the scientists who are boosting it. They confidently dismiss warnings about “three-parent embryos” but they speak very vaguely about the risks to the child’s health inherent in “mitochondrial transfer”. At its best this is hype; at its worst it is cynical manipulation of public ignorance.  

The scientists are playing with fire. As science communication expert Matthew Nisbet points out, “As in the case of climate change, each time a scientific claim is proven false or inaccurate; it risks further alienating publics already distrustful of the science and scientists.” 

Michael Cook
Scientists are soft-pedalling the health risks in so-called “mitochondrial transfer”.
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