Imagine you have a button on the wall you could press which would which would eliminate schizophrenia in all people born after say January 1, 2017. Would you press it?
That is not the way I picture genetic engineering working, at least in the near future. Instead, the question might be posed as, “This gene raises the probability of schizophrenia by .03, but it also raises the probability of artistic genius by ___. Would you like us to edit that gene out of your offspring?”
To put it another way, if there is a single gene that caused schizophrenia, and it has no beneficial effects that compensate, then how does that gene persist?
My amateur understanding is that many characteristics are determined by multiple genes, and many genes have multiple impacts. That means that for genetic engineers the choices will not be clear-cut for a long time, perhaps never.
I imagine a progression from low hanging fruit to ones further up the tree. Lactose tolerance might be an easier one, for instance. There are also probably lots of genes where the trade off was more important in Malthusian or ancestral environments, but which don’t concern many of us much now. Anything that costs extra calories, like maybe an Olympic athlete’s metabolism or extra brainpower is in this category. Calories are plentiful and cheap now.
Yes, or those requiring certain specific inputs to convey an advantage, like protein or amino acids, fatty acids, etc.
Agreed with your overall assessment. Too complicated to forecast. Research important, don’t put hopes into it solving all problems.
As a Type 1 diabetic though, that problem seems easier to solve then editing the brain. I think a lot of people with physical ailments are in the same boat. Have hopes for my descendents.
In the case of schizophrenia, doesn’t it normally impact people later in life? For most of human history, people might have already had a few children before the symptoms manifest.
Isn’t there a pretty robust body of evidence that the only negative trait associated with greater intelligence is nearsightedness? That greater intelligence means happier, healthier, longer-lived, wealthier, kinder, more charitable, more law-abiding individuals?
Probably there are hundreds and thousands of genes associated with higher intelligence, so we are probably a long time away from doing anything intentional to raise a child’s IQ, but intelligence seems to be the low-handing fruit to focus on for genetic engineering.
I think it was Geoffrey Miller in “Spent” that said intelligence is the one trait that humans universally want more of in ourselves, our friends, our partners, and our children (whereas with other traits – like openness, or height, or pick any other trait – there’s not a universal preference for “more” of that thing).
Yeah thankfully a lot of desirable traits are also associated with better mental & physical health so I doubt whether these tradeoffs are going to be a big practical challenge.
darker questions:
“this edit will assure your child will never break the law, but as a tradeoff they will be utterly spineless in the face of oppression”
“this edit will assure your child is never afflicted with cancer or dementia, but they will drop dead at 62”
how dark and evil does the edit have to be before society tries to disallow it? and what factors will cause that suppression to be more or less successful than attempts to suppress addicting drugs?
They just gave a bad example. There are many diseases that result from point mutations (in other words, only a single gene needs to be edited for it to be fixed). Examples include cystic fibrosis, sickle-cell anemia, and Tay-Sachs disease. Like you said, however, most diseases do not work this way.
The way diseases like these get passed on may have to do with their codominant effects. In the case of sickle-cell anemia, it has a beneficial effect if the individual has only one copy: they are more likely to survive malaria. The problems only occur if someone has two copies of the gene.
Yes, correct – it’s that causal density thing again.
There are some ways that it can work counter-intuitively however.
Some traits may not reveal themselves until the organism has passed reproductive age so there may not be the same pressure for it to be removed from the gene pool. So genes that confer susceptibility to some cancers or mental health for example may not appear until later in life and the gene has been safely passed on to the next generation.
Also, some genes confer negative traits when present as 2 copies – 1 from mum, 1 from dad – and may in fact be advantageous.
Cystic fibrosis is like this – 1 copy confers a more infection-resistant mucosa, 2 copies the disease.
Another is sickle-cell – 1 copy is resistant to malaria, 2 is disease.
Interestingly biologically deterministic arguments around the paradox of homosexuality are similar. 1 copy confers bisexuality, 2 exclusive homosexuality – and thus the paradox of the gene persisting in the population. Population gene frequencies appear to match the predicted frequencies.
All highly speculative of course.
We can of course and do screen for CF prenatally and the parents can be offered a termination of their child should they wish – at least here in the UK – not sure if it’s the same in the US.
This and other prenatal diagnostic investigations can be considered to be a form of genetic engineering.
IVF takes this a step further by enabling the ex-vivo embryo to be diagnosed before re-implantation. This represents a much more slippery slope of course with parents perhaps being able to “choose” certain characteristics. Ethically staff are not allowed to inform the parents as to the sex of their child.
The slippery slope ethics are also quite murky in the case of Downs Syndrome. This condition is considered by some to sit within the range of normal human behaviour. Whether or not therefore testing-termination should be available in these cases is a matter for … our elected representatives I guess, acting so as to extract the wisdom of the crowds?