Here is a likely poorly-specified question for biologists, prompted by wanting to buy Alan Weisman’s The World Without Us and then reading a story about genetically modified mice. Weisman’s book asks how the world would change and what of us would survive if humans were all wiped out overnight or just disappeared by something (a virus, the Rapture). The premise is unlikely (something that kills people—all people—but leaves the rest of the world standing) but intriguing.
So I wondered, what if, long, long after our disappearance, some other species arose on earth at least as intelligent as us and eventually started doing evolutionary and molecular biology. Let’s say they have a working theory of evolution much like our own. Now say for the sake of argument that a bunch of transgenic organisms produced by humans have survived and prospered in the interim. So our future biologists find things like a bacteria that produces insulin, or a plant that secretes insecticide, or rice that is high in beta carotene, or more exotic stuff as needed.
I’m wondering, would such organisms even present themselves as empirical anomalies? (That is, how much would you have to know about genomes and evolution for them to seem odd?) And if they did seem odd, how would they be explained? That is, would the evidence of their intelligent design by a previous, now-extinct species be clear? You can see that I’m just irony-mongering here. Would some Arthropod-staffed functional-equivalent of the Discovery Institute point its claw at some of these organisms, saying they were anomalies that could only be explained by the intervention of a divine intelligence? Would Charles Crustacean find a story that could account for their evolution by natural selection? I’m particularly interested in whether the artificial provenance of transgenic organisms would be clear on internal evidence alone. I don’t know anything about this stuff, so probably the answer is “Yes” for reasons obvious to experts. But if it weren’t …
From the sound of Weisman’s book, though, internal evidence wouldn’t be all that was available. Our putative Arthropod successors would likely be able to conjecuture as follows: “The lost civilization who did this is probably the same one responsible for leaving those giant goddamn piles of steel-belted rubber rings and miscellaneous plastic items piled around the place.” To which someone would no doubt reply, “Come off it, no organism that spent its time making rubber tubes and piling them up in giant mountains would have ever been smart enough to figure out genetic engineering.”
 It occurs to me that rice requires a lot of cultivation to prosper, but there aren’t any humans to take care of it. Hence, “insert example as needed.”