Natural Selection Makes Itself Extinct Through Genomics and Pre-Implantation Screening

By Jeremy Grushcow

The “end of evolution” has been announced before. A few times over the last 10 years, authors have pointed out that we have altered the fabric of natural selection (e.g., with my myopia, I should have been stepped on by a brontosaurus long before reproducing) or the inputs for speciation (e.g., in a flat world, there are no isolated populations).

Natural Selection Makes Itself Extinct Through Genomics and Pre-Implantation Screening, Altitude AcceleratorBut the basic Darwinian event — meiotic recombination and sexual reproduction throwing our alleles in a blender and the resulting offspring being tested in the crucible of life (the crucible of LavaLife?) — has until now remained intact.

No more. A recent post by Daniel MacArthur at the (always excellent) Genetic Future blog called “One more step towards the end of recessive diseases” discusses a technique to test prospective parents. This concept is not new — most Ashkenazi Jewish couples already undergo some pre-conception genetic testing for recessive disorders — but MacArthur describes a new technique to assess “the entire sequence of all genes known to be associated with Mendelian diseases.”

What is to be done with this screening information, though, and what do we do in the near future when we can cost-effectively sequence the entire genome at the cost of a routine diagnostic procedure?

Let me put it bluntly: I’ll bet you a million petri dishes that my kids* will not conceive their kids** naturally. Embryos’ genomes will be sequenced before they are implanted and parents will select — not naturally, but by rigorous computation of multivariate risks — which embryo will compete in the next generation.

MacArthur might take the other side of that bet, claiming that “it still seems fairly implausible that [In Vitro Fertilization] will become the default mode of reproduction in the near future.”

How much longer will we pick embryos by the winner of a sperm race? I have weighed in on this before, and a 2006 EMBO Reports article by Armand Marie Leroi that MacArthur cites hedges eloquently…

On the one hand:

“nature has contrived a cheap, easy and enjoyable way to conceive a child; IVF is none of these things”

On the other hand:

“It seems possible that … an increasing number of parents will choose not to subject their children to the vicissitudes of natural conception and the risk of severe genetic disease”

One thing we all agree on is the incredibly powerful motivation parents feel to ensure that they have healthy children. MacArthur says “[p]arents, as a group, will simply do whatever it takes to increase the probability that their children will be born healthy” and Leroi backs that up with data showing a high rate of abortions of fetuses with medical problems, despite the stress and physical and emotional challenge of that decision.

Why wouldn’t PGD become the dominant mode of reproduction? Cost is an issue, but Leroi makes a solid economic argument for the testing, which suggests payors will fund the procedure. Another objection could be to the genomic sequencing aspect, but new data this week from a Scripps study shows that consumers are perfectly comfortable receiving genomic information about themselves.

All of this requires concrete thinking about Ethical, Legal and Social implications so that when the “natural way” stops being the normal way we have an infrastructure in place to distinguish health from eugenics and to protect the privacy of the first post-evolutionary generation.

Get ready.


* Now 7 and 9.

** Now approximately -20, one hopes.

Re-posted from the Cross-Border Biotech Blog

Jeremy Grushcow is a Foreign Legal Consultant practising corporate law at Ogilvy Renault LLP. He has a Ph.D. in Molecular Genetics and Cell Biology. His practice focuses on life science and technology companies.

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