I think a lot of our diseases if looked at genetically instead of symptoms-wise that we will probably find out that it's actually multiple conditions that we just group together for manifesting in similar ways. I've felt this in my own life with ADHD things where it seems to me that there are at least 3-4 different types of ADHD and that they respond to treatments/medications differently, and this makes me think that many other conditions might be similar, especially if we start looking at them genetically.
This is such a deep hole of complexity. (My wife is a pharmacist, I make computers do what I tell them to, and she has convinced me that her field is far more complex than us software people can imagine.)
To pick one story my wife has told me, take the example of Multiple Sclerosis. In the 1970's and 1980's, thanks to the MRI machine, there was finally a good diagnosis tool for MS: can you see the lesions in the scan? If you can congrats, you have MS. If you can't, it might be early MS where the lesions are small enough that we can't see them (generally they are visible several years after initial symptoms). But there were a lot of people who had MS-like symptoms and no lesions, so diagnosis of Chronic Fatigue Syndrome (named just in 1970, in contrast to MS which was identified in the 19th Century) started to rise. Most of those people would have been diagnosed with MS in 1950, but now we can rule that out and so they go into the new bucket instead. What is going on with patients in that CFS bucket? It's a mystery. Is it one thing or many? Who knows! Is it genetic or environmental? Who knows!
And how does one get original flavor MS? It's not fully genetic- comparing identical and fraternal twins we can see that it's not purely genetic but there must be a genetic influence. The current most accepted theory, according to my wife, is basically Long COVID- but for the Epstein-Barr virus (what causes Mononucleosis) instead of COVID-19. So if your immune system is somehow susceptible to this (the genetic component, which we apparently do not understand), and it encounters EBV (and there is a bit of bad luck? Who knows!) then somehow the immune system gets confused and starts attacking your own nervous system.
We computer people are simply attacking much more tractable problems.
There are multiple brain conditions that are increasingly being suspected of being caused by viruses. They are the ultimate DNA editors. And some can remain dormant for decades before reactivating.
Which is why it was so puzzling to see the response during the last pandemic. More so with people concerned about mRNA vaccines and conflating that with 'DNA changes'. If one is concerned about their DNA, they should avoid viruses and do whatever they can to help their immune system fight them as quickly as possible.
The odds of a virus giving us something beneficial like a placenta are minimal, the drawbacks are just enormous.
