[quinndupont]

This assessment strikes me as precisely correct. This article gets dangerously close to click-bait academia, since while it (presumably) does good science, the abstract highlights this sensational-sounding result, that the authors must know will get picked up by the public.

That 1/2 of the DNA is of unknown origin does not mean it is somehow really weird or alien (as the public will imagine), rather, it just means we don't know all that much about extant DNA.

[giarc]

I agree. The whole "NYC Subway" could be replaced with any transit vehicle in any town/city and you would get the same results. Nothing special about NYC subway.