Archive for March, 2015


Some scientists make no sense to me

Saturday, 21 March, 2015

There was an opinion piece published in Nature recently called Don’t edit the human germ line. It’s written by leading scientists (Edward Lanphier, Fyodor Urnov, Sarah Ehlen Haecker, Michael Werner& Joanna Smolenski) in somatic cell gene therapy, and to me it reads like they’re very concerned that the association between gene therapy in adults and the concerns about making designer babies would lead to public outcry over gene therapy. Basically they’re trying to shut down germline engineering so they don’t look guilty by association (especially given the same techniques would likely be employed).

The authors do point out a lot of technical issues with embryonic genetic manipulation, namely that any errors or side-effects might not appear until years later. Which is fair, in my opinion. I still think it’s pretty likely that people won’t genetically modify the human embryo until the technology for doing so in consenting adults is well established.

But in the article, the scientists make a few stupid statements. Like saying

We are not, of course, making a comparison between the replacement of faulty mitochondrial DNA in an egg or embryo with healthy DNA from a female donor and the use of genome-editing in human embryos. In mitochondrial transfer, the aim is to prevent life-threatening diseases by replacing a known and tiny fraction of the overall genome.

I don’t see why they wouldn’t make this comparison, because it seems basically identical to me. I will concede that editing the mitochondrial DNA component of the genome is technically a lot easier than editing a small component the nucleic DNA component (due the former already being isolated in the cytoplasm). But ethically, it doesn’t matter if you’re trying to edit the mitochondrial DNA or a gene contained in the nucleic DNA, you’re still aiming “to prevent life-threatening diseases by replacing a known and tiny fraction of the overall genome”.

The scientists also seem to tie themselves in a loop with two parts of their argument. The first is this:

Philosophically or ethically justifiable applications for this technology — should any ever exist — are moot until it becomes possible to demonstrate safe outcomes and obtain reproducible data over multiple generations.

Aside from the extreme lack of foresight in doubting the obvious benefits of germline genetic engineering*, this seems a fair point. While the science is in its infancy, it seems wise to be very cautious. But combine this point with a point made in their closing argument:

A voluntary moratorium in the scientific community could be an effective way to discourage human germline modification and raise public awareness of the difference between these two techniques.

Hardly a suprise, given the title of the article, that the scientists are against germline engineering. But how is anyone going to be able to :”demonstrate safe outcomes and obtain reproducible data over multiple generations” if there’s a moratorium and it’s illegal to do those experiments?

Basically these scientists, instead of trying to address the concerns the public has over the ‘scary’ idea of designer babies, are just trying to say “Yeah, designer babies are scary but that’s not what we’re doing at all, so please keep funding us”.

*There are a whole host of genetic diseases that have to be fixed before the development of organs and tissues, so our only option to cure these would be to edit the genome of a gamete (sperm or egg) or embryo. There would be no way to use somatic cell gene therapies after birth for these conditions, especially for those conditions that often result in death shortly after birth. In most but not all cases you could, as the authors suggest, use pre-implantation genetic diagnosis (PGD) to select only for embryos without these mutations. But in some cases both parents might be affected by a recessive genetic condition, so there would be no embryo without the mutation to choose, thus ruling out PGD as an option.