Once we get past the diseases research, what's stopping us from going further? Could we discover e.g. a DNA sequence in human genome "linked" to higher intelligence, or better leadership qualities? And if yes, what can guarantee that instead of the Nazis' "master race" based on pseudo-scientific scull measurements we won't discover "master genes" based on actual DNA science?

What frightens me is not what we can discover, it's what we as human society will do with that information once we discover it.

I think we're past that. Setting aside politically hot topics like IQ, Height is genetically determined and makes a huge difference in life outcomes. Now it's all about what we do with that information.

You can tell a person's height just by looking at them — unlike other examples, you don't need any advancement in DNA science for that.

That makes height an easy topic to talk about, but it's still challenging to think through the implications. If you can increase your child's height by 20% and thereby increase their likely income by 25% - is it morally right not to? Does it matter whether others can afford that intervention? Is it morally right not to fund public access to such interventions? Does the answer change if relative height is all that matters?

On height, that is already a reality.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5956020/

https://www.statnews.com/2019/11/18/a-new-treatment-promises...

I mean, read up on the history of eugenics. Mainstream establishment science has come up close to doing exactly this sort of thing in the past (including sterilizing people who were considered "unfit").

It seems almost certain that we will continue to find more DNA sequences that are correlated with increased intelligence.

Because DNA won't tell you whether the genetically-genius person smashed their head on a rock and is now totally unfit for your high-paying engineering job.

Nor will it tell you whether the genetically-average intelligence person spent 14 hours per day for the last 8 years in the code mines building awesome stuff.

I.e. it won't tell you the types of things that interviews are designed to suss out.

Any test mixes signal with noise (Maybe that superstar candidate is just awful at interviews? Maybe the super lazy coder puts their laziness aside only for the interview day?)

Combining many noisy factors into one, with the correct weighting, will always, on average, give better results than a single test.

That means that as soon as DNA tests give even a weak prediction of 'iq' or 'leadership abilities', companies will integrate them into hiring processes if legal and cheap.

If there were single genes that produced high intelligence scientists probably would have found one by now. Those sorts of traits are almost certainly highly polygenic. Any single gene is likely to have both small and unpredictable contributions to the traits in question. Even totting up all your "good" and "bad" genes to try to come up with a genetic score is fraught due to complicated interactions; perhaps two "good" genes interact badly and make a bad result, or similar.