[vadimberman]

> Ata’s bones contain DNA that not only shows she was human

The fact that there's a DNA already means it's not an alien, doesn't it? Having a life form with the same uber-complex chain of nucleotides as the life on earth developed is as improbable as a server on an alien mothership being compatible with a Macbook. (Quick primer on the subject: https://www.airspacemag.com/daily-planet/cracking-aliens-gen...)

Having said that, the NYT article reads like the researchers are still unable to explain the discrepancies between the age and the well-formed skeleton as well as the number of mutations. Were there any secret nuclear tests conducted half a century ago in Chile? But that would also probably be insufficient to cause all that. I would bet on experiments trying to cause deliberate mutations.

[seiferteric]

Not if you believe in panspermia.

[vadimberman]

It depends on the kind of panspermia.

If it's about generic organic molecules then the DNA is a local construct. If it's about microorganisms, then it's different.

[seiferteric]

True. It's also possible that DNA is the only form of life that really works, but we just don't know yet.

[lovemenot]

There's 6-base pair organisms now. https://www.sciencealert.com/new-organisms-have-been-formed-...

Also, RNA seems to work and it's possible we started out using RNA and later evolved to DNA.

[bordercases]

It excludes other bipeds or apes.

[pvaldes]

Not necessarily. Can be also a contamination from an external source of DNA. The article claims a mixed chilean-european DNA but we don't know how many moved humans had touched this skeleton before

And there is the fact that we share DNA with other species. It seems [1] that we shared a 93% of DNA with Macaca mulatta for example.

[1] https://www.livescience.com/1411-monkey-dna-points-common-hu...

[bordercases]

On that second point, charitably we can assume that they found a marker which is uniquely human. Although yeah, could be contamination.

[slphil]

I don't know any other hypothetical building blocks for complex life. It could possibly be the case that the alternatives are too unstable and that alien life would be made of something remarkably similar to (but obviously not identical to) Earth DNA.

[vadimberman]

There's RNA and possibly others even on this planet: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3331698/