Recently I was having a discussion with some friends about getting the full genomes of everyone in my immediate family when the price point comes down to $1,000, just as I have had my immediately family genotyped. You can find some interesting stuff just from the genotype alone, which for current affordable platforms aims for ~1 million variant markers out of ~3 billion base pairs. For example, I inferred that two of my siblings have a coefficient of relatedness of ~0.41, 3 standard deviations below the expectation of 0.50. Another way to put it might be that they’re 1/3rd of the way to being half-siblings! With whole genomes the opportunities are even greater. You could for example ascertain the distribution of novel mutations by comparing parental genomes to offspring. I also began to consider the fact that we might start developing intuitions about the expected number of new mutations a child should have based on how old their parents are.
This led me to reread Armand Leroi’s 2006 piece, The future of neo-eugenics. Now that many people approve the elimination of certain genetically defective fetuses, is society closer to screening all fetuses for all known mutations? One particular section jumped out at me because it is surprisingly dated for a five-year-old essay:
One impediment to a universal, total prenatal screen for all known mutations is the invasive nature of the procedure—it requires amniocentesis…or chorionic sampling to retrieve cells from the amniotic sac—and the traumatic nature of the treatment, which is therapeutic abortion. Perhaps, then, a total mutation screen will not be used in prenatal diagnosis, but rather in preimplantation genetic diagnosis (PGD). This procedure tests embryos produced by in vitro fertilization (IVF) for chromosomal abnormalities and specific mutations before implantation, by removing a single cell from the embryo at the eight-cell stage. Healthy embryos are then implanted; poor embryos—showing one or several abnormalities—are frozen or discarded. As in prenatal diagnosis, PGD is generally carried out only when a family medical history suggests that the embryo is at risk of a specific disease….
Within the next few years we’ll be able to ascertain a fetus’ genotype from a simple blood test. I think this is going to make a huge difference. Amniocentesis and CVS are both stressful for expectant parents, because you’re told repeatedly about the miscarriage risks. With a blood test the barrier to entry is reduced considerably.
Another aspect of the essay is that in 2006 I recall many people feeling that Leroi had not addressed ethical objections to this sort of procedure robustly enough. But at this point it seems as if a lot of the developments which he foresaw are near fruition, and people aren’t making a big fuss about it. Why? Because it’s one of those things that happens gradually, and the potentially ethically dubious becomes normalized.