Razib Khan One-stop-shopping for all of my content

January 7, 2012

PGD:2010s::IVF:1980s

Get ready for PGD, the acronym for preimplantation genetic diagnosis. We don’t really talk about “test tube babies” anymore. It’s “IVF,” and as American as apple pie (OK, perhaps as Israeli as falafel). Here’s the Ngrams result:


It’s just not that big of a deal anymore. But take a look at the order articles in The New York Times. There was a day that peopel were very worried about what “test tube babies” entailed. The end of the world as we know it? If that happened I don’t see anymore complaining.

The Globe & Mail in Canada has a very long piece on PGD, Unnatural selection: Is evolving reproductive technology ushering in a new age of eugenics? I do think it is ushering in a new age of eugenics, though it doesn’t go by that name. Many of the issues I’ve brought up on this weblog, such as the incentive for governments which fund national healthcare to take a deep interest in sifting through the range of future taxpayers and consumers of services, are explored. My basic instinct here is much more libertarian than most people. As a practical matter I’m rather close to a maximalist in terms of the amount of latitude I think parents should be given in selecting the nature of their offspring. But, I’m not a libertarian in an absolute philosophical sense, and I think a broader discussion in a society where the state and majority have coercive power over individuals is warranted.

There are two minor technical angles that I do want to bring up though:

- PGD seems to be ideally tailored already for people who marry their cousins. It would be relatively good at screening for the many recessive diseases which are common in the children of cousins. Also, it might even be able to reduce the fraction of runs of homozygosity through judicious selection. So, in the near future Muslim nations might be major consumers of PGD (Muslims as a whole are moderately anti-abortion, but they take a much more pragmatic line on these issues than the Roman Catholic church).

- PGD for trait selection runs into some statistical genetic difficulties. But, I wonder if perhaps PGD for decreased mutational load might be useful? With high coverage full genome scans could not one ascertain with good precision which genes have been subject to inherited or de novo deleterious mutations? It is generally assumed that loci where there is a major deleterious mutation masked by a normal functional copy still induce some fitness drag on the individual. The range in outcomes in siblings may be part of the natural variation in the mutational load. Parents may be tempted to lop off the asymmetrical-faced end of this.

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