[achenatx]

all viruses are susceptible to UV light. Ultimately it spread in bats so it is pretty obviously able to spread in caves. It also spread in people indoors.

There is virtually no way for scientists to look at DNA and say "oh yeah this was manmade" (or not manmade). Possibly if there is some really obvious splicing marker used or something.

the entire sequence can be put into a computer and custom generated.

[groby_b]

There are, however, strong indications. I don't have my cites handy, but IIRC for COVID, they were twofold. One, it relied on a mechanism that pre-COVID was considered ineffective/borderline for spread, and that actually doesn't work well in simulations - so it's unlikely humans would've picked that. Two, it's closer to typical bat viruses than typical coronaviruses - again, an unlikely choice for humans to make.

Ah, here we go: https://www.livescience.com/coronavirus-not-human-made-in-la...

No, that doesn't rule out manmade 100%, but it makes it quite unlikely. It's essentially saying "hey, I built a virus in a structure that doesn't rely match a well-working virus class. Also, it completely fails to do what we want to do in simulations. We should invest a lot of money to build that".

Occam's barbershop would like to point out the very high number of unlikely events required to go down that path ;)