The Return of Eugenics

20 04 2010

Eugenics has a bad rap. All that talk of selective breeding (or sterilising) of people in order to improve the human stock or purify races is terribly distasteful today – and for good reason. However, I wonder if we’re already bringing a kind of eugenics back with modern day genetic testing. And if so, maybe this, much more temperate, version of eugenics is acceptable, or perhaps even good.

Prenatal testing and embryo testing for hereditary genetic abnormalities and disorders is on the rise. We now have the technology to not only determine whether an embryo or a foetus carries a genetic defect that will result in a life threatening disease or disorder, or even one that will severely compromise standard of living, but we can even screen embryos before they’re implanted through IVF.

Certainly, there are broad grey areas over when and in what circumstances such testing can occur – I’m not about to debate these issues – but I am assuming that such tests, in some form, are likely to continue. And, by continuing, we will further have the ability to screen embryos that carry such disorders.

If, by doing so, we reduce the representation in the human gene pool of genes that cause certain disorders, and we do so willingly, then, in a manner of speaking, we’re engaging in a kind of eugenics. Not the kind that attempts to selectively breed (or genetically engineer) to seek out or enhance certain phenotypic traits, but the kind that ends up reducing the frequency of some undesirable traits. One needn’t even start allowing parents to select traits, like eye colour or height, for this weak form of eugenics to hold.

Put this way, my initial suspicion surrounding eugenics gives way slightly to the prospect that this might even be a good thing. But there are still issues, like that we might be inadvertently reducing our genetic diversity, and this could prove problematic down the track.

There are very few (if any) genes that affect only one thing. Genes code for proteins or RNA, and these proteins and RNA can perform multiple tasks and interact with other proteins or RNA in complex ways. Reducing the frequency of one gene in a population might have unforseen side effects. One need only observe the problems that arise when genetic diversity drops significantly – such as in so-called founder populations – to see the ill effects of a lack of diversity.

Then there’s heterozygosity, such as with sickle-cell anemia. It’s a genetic disorder that is inherited if an individual receives two copies of the mutant haemoglobin gene; if an individual possesses only one, the non-mutant is dominant, so sickle-cell anemia doesn’t develop. Furthermore, heterozygous individuals – those who have a mutant and non-mutant gene – gain some resistance against malaria. Eradicating the mutant gene from the population could have a negative effect in terms of malaria resistance. That said, if homozygotes were screened, that alone wouldn’t remove the mutant gene from the population.

I doubt this will ever be a simple black and white issue. There are likely to be plenty of cases where prenatal testing will reveal some non-inherited genetic abnormality, such as Down syndrome, which is not a heritable disorder (although individuals with Down syndrome can have children – if rarely – and they are more likely to carry the syndrome). And we can employ limits and precautions on how we treat the presence of heritable diseases or disorders – or the presence of genes that might increase the chance of a particular disease or disorder. With some cautious use, we might lower the proportion of genes in the population that cause these problems, but not eradicate them altogether.

I don’t know if you’d call that eugenics – admittedly it is a stretch – but even if it is, with some caution, it might actually be a good thing.

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5 responses

21 04 2010
James Gray

There is a lot of unintentional eugenics as well. Throwing people in prison, making health care unaffordable for many, and making it difficult to have a good career while being a parent are all examples of social behavior determining what counts as a reproductive advantage.

21 04 2010
Tim Dean

But that assumes a link between genetics and behaviour that leads to prison or to a good career. There may be some genetic influence on such behaviours, but they’re likely to be largely steered by environmental forces. The old eugenics did believe that if you prevented prisoners from breeding, then, one day, there’d be less people going to prison, but I believe that’s a non sequitur.

The prenatal screening for genetic disorders I mention explicitly results in removal of genes from the gene pool, and we know these genes do have an effect (even if we don’t know them all).

21 04 2010
James Gray

Yes, environmental factors are also relevant, but that doesn’t stop the genetic influence. Lots of non-white minorities are going to prison, for example.

23 04 2010
Tom Rees

Have you seen Eric Kaufmann’s recent book Shall the religious inherit the earth. I have not yet got far through it, but it looks very interesting. Essentially, the point is that fundamentalists are more fertile than others (religious and non-religious). Now, what evidence there is suggests that there is a fairly strong genetic component to fundamentalism, which suggests there is an evolutionary advantage – at least in the current environment. An evolutionary advantage to fundamentalism. Now there’s an irony if ever I saw one!

27 04 2010
Tim Dean

I haven’t read the book, but I’m familiar with the argument. But I don’t necessarily buy in to it. I don’t doubt that genes influence our beliefs by affecting the way we respond to the world around us. And I don’t doubt this can account for some aspects of fundamentalism.

But I don’t think there’s any real risk of being ‘out bred’ by religious fundamentalists. Firstly, religion is pliable and changes over generations and with economic standards. Those in more liberal countries have more liberal attitudes – yes, even American Christians (compared to tribal fundamentalists). And the hardcore fundamentalists are still a minority in these groups – most are moderates.

Also, even if there is a selective advantage to being dogmatic, it’s unlikely dogmatism will reach majority levels. My understanding is these traits are like strategies in the Prisoner’s Dilemma, and we’d expect to see an equilibrium (if a dynamic one) of alternate strategies. Too many fundamentalists would be unstable and liberalism will bounce back.

Finally, where there’s a spectrum for a particular trait – say, intelligence, height, or introversion/extroversion – they tend to gravitate towards the mean with every generation. So two highly intelligent, tall, fundamentalist parents will tend to have, on average, slightly less intelligent, tall or fundamentalist children.

All these things suggest that we might see the odd spike in these traits, but they’ll work their way back to an equilibrium. That said, we shouldn’t stop working to erode fundamentalist beliefs – and building a strong secular alternative to religion. The more we can do that, the better off we’ll all be.

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